Flexi brake lines

 Well, there goes another two months. I count myself lucky that I have a job during these times, but I also wouldn't have minded a bit of time to work on the car. I'd have had it done by now! Well, not registered, but definitely built.

Anyway, the flexi brake pipes arrived, and I immediately realised that the original brake pipe brackets were far too small. So I've had to cut them off and replace them with some more made up from 3mm steel. Still, it gives me an opportunity to route the pipes properly.

This is what I have on the outside and inside;

It seems quite a smooth line, with the connector routed nicely to the copper pipe. The outer works well with the steering left and right;

But checking this with other pictures suggest the pipes just go direct from the caliper to the chassis, with no support. That seems wrong to me, a loose pipe in mid air that has to have some flex in it? Not convinced.

I'll see what the locost builders reckon, and adjust as necessary. 

*** UPDATE ***

Turns out I was way off the mark! It shouldn't be fixed to the wishbone, the movement would cause chafing and therefore would be an IVA fail. So despite me thinking it's a bit 'odd', being held in free air is actually the right way to do it. I think I could get away with it if I used rubberised P clips to secure it, but it's adding a complication and possible failure point where there is just no need for it. 

Now the issue is that I measured the lines based on it going via the wishbones, and with that no longer being true I need to figure out how to route them while taking into account the extra length. They're about 5 centimetres longer than the 'standard' measurement, so 500mm rather than 450mm. I don't really mind them being longer, it's definitely better than being shorter! I just need to figure out where to place them. 

Results from the weekend part 2: The handbrake

 Putting everything together for the brake flexi hoses made me remember something I'd decided on a while back. To get the rear suspension behaving itself I worked out that the uprights should be 'backwards'. IE the left will be on the right and vice versa. 

This had the positive outcome that the suspension bracket could be correctly fitted, but had the negative outcome that the calipers were on the rear. When I was doing the suspension I thought it would be a minor inconvenience compared to the much bigger problem of redesigning the suspension.

The 'minor inconvenience' might be a bit more of an issue though. I also have the added complexity of wanting a dash mounted handbrake (see the post from last week). This means that custom cables were guaranteed but I'm really not sure whether this sort of safety device is easily DIYable. A quick post on Locostbuilders suggests it's not that much of an issue for two reasons. One was that many people have redone the Sierra handbrake in order to get it to fit. The other is that I can use more of the standard handbrake than I thought I could.

So this weekend I've spent a couple of hours freeing up the adjusting mechanisms on the cables. They took ALOT of work considering it's basically two nuts on a threaded tube!

The next job will be to put the suspension together (again!) and try and route the cable safely. The cable has got to come out the caliper towards the back of the car, then do a u turn on to the chassis (probably close to the brake pipes if I can get it to work). They then need to head up the centre of the car to reach the balance bar (oh yeah, I need to find out where that ended up!!), then onwards to whatever mechanism I'm using for the handbrake itself. 

I'm going to try and keep the rear cables as standard as possible, but the front one I think will have to be modified. After all, it's not even going to a handbrake! 

I'll get the rear rebuilt and take some photos so I can work it out... but that's it for this weekend. 

Results from the weekend

I managed to get some jobs done over the weekend, although the extra hour in bed did help. It does mean that there are no more light evenings, and it just gets colder from now on.

Still, jobs done. The first thing was to tidy up the hubs and uprights. They took a bit of a beating when I took them apart, in parts the metal was exposed. So back with the hammerite and black primer. It wasn't a major job, but it had to be done before things could go back together. 

The next job with those uprights was to work out the lengths of the brake flexi hoses. I had to basically build the suspension front and back on one side. That was an interesting experience, I'd forgotten how they'd gone together!! Still, after a few trials I got everything lined up and ready to measure. I had to get my shiny calipers out of storage too, the first time they'd felt fresh air since I reconditioned them and bagged them up.

I used the remnants of an extension lead to figure out the length. The wire was fed through the chassis brackets with the plug holding the end. The wire could then be routed to the caliper, keeping things smooth and not too tight. The fronts weren't too bad, just needed a bit of slack to cope with the steering and suspension movements. The rears needed a bit more thinking though.

The main issue is that the chassis brackets as suggested feed the flexi hoses straight out the side of the car. It's then a bit of a mission to get them back to the caliper without getting close to the wheel itself. This was especially relevant because my rear suspension setup had the caliper on the back of the disc rather than the front. This means both the hose and the handbrake would be heading towards the back of the car initially. 

After a few minutes trying to find a solution I decided to abandon the standard position. The plan is to have the flexi hose feed down from the caliper to the lower arm. Then pinned to the lower arm until it gets to the chassis. The chassis bracket will then be mounted at a suitable place, along the diff cage metalwork. 

I'll have to cut off the brackets and reposition them, not a biggie. At least it meant I could get the flexis ordered though, which is the first battle. I got them from Furore, they do custom flexis in a range of ends and colours for £20-£30 a corner (depending on length). I'm staying with the standard MX5 fittings, so it's a 10mm banjo on the caliper, going to an M10x1.0 female at the bracket. They come with a circlip and the copper washers so they should just bolt straight on. £102 for a full set, I was probably a bit over-cautious on the length but as they say, better to be too long rather than too short. 

Oh yeah, the handbrake. Separate post methinks...

Handbrake

 One of the things I've had in mind all the way through is the idea of an underdash handbrake. The demo HSR car had a handbrake right under the steering wheel, and while I was unsure about it being in direct range of my knees I couldn't argue with the clean look of the centre tunnel. 

The main issue is that it was still a handbrake, IE it was still the same handle and mechanism that would have been in the tunnel. This made it look odd (as well as the aforementioned knee impact). Other cars have had similar mounted handbrakes, and a quick google suggests there are much better options.

The easiest one to replicate would be the one used in some cars in the 90's. It was basically a pull rod inside a tube, attached to a cable and then on to the mechanism. 

There's a couple of things to consider though, the ratchet mechanism and the mechanical effort required to apply the brakes. 

The ratchet mechanism was achieved by having slots cut into the pull rod on one side only. To release the ratchet the handle would be twisted so the pawl no longer engaged. 

The mechanical effort needed some maths, based on the existing handbrake. The following measurements were made;

1. Distance from pivot to cable channel = 34mm.

2. Distance from pivot to handle centre = 240mm.

3. 19 clicks on the ratchet mechanism for full travel.

4. 45 degrees of travel for the handle.

The distances from the pivot means that the mechanical advantage is 240/34 or 7:1. IE the handle moves 7 times further than the cable. 

The cable travel is Pi x 68 / 8, or 26mm from stop to stop (the actual travel is less than that but I'll maintain the full travel distance for now). The same travel for the handle is Pi * 480 / 8, or 189mm. 

This means that I need to come up with a mechanism that moves 189mm on the lever, to 26mm on the cable. It shouldn't be too difficult, except that it's 'the wrong way'. The pull handle will come out towards the driver (front to back) whereas the cable needs to pull from back to front. A bowden cable would achieve this quite simply, but that would reverse the action without applying mechanical advantage. It would also add friction which would mean more effort and/or pulling distance. More than 7 inches is already a far pull distance, I wouldn't want it much longer.

I need to come up with a solution to apply the reverse in direction as well as operate the change in ratio. Time for some Fusion 360 I think!

Oh, for the ratchet mechanism, I counted 19 clicks on the ratchet. To have the same on the pull handle would mean 19 notches on the 189mm of pull, or 1 every 10mm. Not a problem. I need to have a spring loaded pawl to operate on the solid rod of the pull handle within the hollow tube of the slide. This is a little more of a problem but still not insurmountable. After all, I already have a handbrake with a pawl mechanism that I won't need anymore!

Bearings

 One of the things that has bugged me with the donor parts has been the wheel bearings front and rear. They didn't feel bad and were never highlighted as an MOT issue on the donor car history, but it seemed really strange to not replace them. The reason I'd not done them yet was simply because I couldn't get them apart!

Reading many forums seemed to agree with my assessment, they're usually so meshed together that they should only be taken apart if absolutely required. And it's very likely that some breakages and replacement parts will be needed. There was also mention of 20 ton presses, scaffolding poles as breaker bars, and all sorts of other stuff.

But doing some further research I could see that replacement parts weren't particularly expensive. On the front the bearing and hub were a single unit, as they are on the rear of most cars. Coincidentally they are actually used on the Mazda Demio/121 of a similar era (1990-2005). So while searching for MX5 front bearings gave a lot of very expensive options, a search for Demio rear bearings got lots of cheaper ones! A pair of hubs/bearings were £46 delivered.

Next were the rears. The stub axles were not going to survive, I resigned myself to that. The nuts were also going to end up in fragments on the garage floor. Fortunately the stub axles contain the CV joint so they're intended to be a replaceable item. These are MX5 items only, but a pair cost £31. They also come with replacement nuts so that meant I could go to town on those without worrying.

The last item for the rears was the bearing itself. Apart from wanting to replace the bearing anyway (the whole point of this exercise) the design of the stub axle means that the bearing collapses when it's being removed. So it has to be replaced. Again, Mazda makde things really simple and had this wheel bearing used by many cars. £25 for a pair, no problem.

This meant a full set of replacement bearings and associated parts was £102 delivered to the doorstep. That's pretty much spot on in my opinion. 

The stripdown was so much more effort though. The four hub nuts got the brunt of the angle grinder and powerfile, and did indeed end up as bits on the garage floor! 

I have a decent hub puller from previous car maintenance, so with a bit of encouragement the fronts came apart quite easily. The new ones will go on, and then torqued up as required.

The rear took much more work to do the same task. In the end I got my impact gun on to the hub puller and just gave it everything I had. The vibrations of the impact gun, combined with the immense pressure that a hub puller can apply, managed to press the stub axle out of the hub. After removing the bearing internals that had just collapsed as expected, the outer race was then hammered out of the hub. Finally the last job was to detach the stub axle from the driveshaft, it was just a spring clip holding it in the same as any other driveshaft so a few thumps with the hammer sorted it.

Once all the parts were cleaned up (CV joint grease is really horrible stuff!!) the parts can go back together again. At time of typing this update the bearings have been pressed into the uprights, and I've done some cleanup on the hubs ready to give them a lick of paint. They had been painted before but access issues meant it was a bit of a rubbish job. 

So that's it for the bearings, everything is where it should be and it'll be ready to bolt back together in the final position. Another job ticked off the list. Well, it was a job added and then ticked off, but it needed to be done! 

No pictures on this one, with the various bits of metal going all over the place and lots of hammering I thought my phone wouldn't last very long. In fact I was fairly accurate with my estimate, I had since found a bottle of beer with a severely dented cap, and I had a pencil torch that ended up in pieces and has been glued back together. 

Pedal setup completion

 Well, it's Sunday morning, the coffee is nice and for once the sun is out, so it's time to get up to date. I've done a fair bit of work over the last few days, actually a bit more than I expected to be able to. 

The first thing to update is the pedals. As I had put in the last update, I had a brake and clutch switch to add. The brake switch was an obvious one, I need brake lights. The clutch switch was an odd one though. Apparently it's to cut fuel on overrun, and it's not difficult to just delete it. So I have!! 

That leaves the brake switch. The action of the switch is to have it closed when the pedal is not pressed, and open when the pedal is pressed. When the pedal is in the MX5 this means it's mounted above the pedal, out of the way of the drivers foot. That doesn't work here as I've turned them over. So I needed to mount it on the floor. This is how I've done it;

It's out the way of the foot, and works as required. It also has the added benefit in that the screw fit of the switch is now the end stop for the pedal. Combined with the screw fitting of the push rod and I have full control over the pedal travel. Obviously where it is at the moment is very wrong, but once the system is plumbed in and pressurised I should be able to figure out a nice place for the pedal to sit. It 'should' only need maybe a couple of inches of travel to apply full force, so it'll be adjusted to do that.

Here's a better view of the same;

Next is the clutch pedal. No switch means no end stop, but the solution was much easier here. The book uses a bent piece of metal mounted on to the bolt itself. So here's the same for mine;

The adjustment is simply to rotate the metal until it's in the right place, then tighten everything up. The screw thread on the push rod also deals with travel. This also needs plumbing in and adjusting, I don't know how much travel is required here but clutches tend to move a lot further than brakes.

Finally the gas pedal was mounted to the chassis. This wasn't a complex one, just a U bracket on to the rail itself. It's spring loaded to assist with pulling the cable, and there's a screw fitted into the bulkhead to restrict travel. I must take a photo of the whole set up, but in the meantime here's a better photo of the final clutch/brake setup;

I am really happy with how it's come out, I'd done the back plate quite a while ago but not finished the process until now. It's had a coat of paint on all the parts and is ready to fit to the car. 

Extra job added

 While I was sorting the loom, I found two switches that I had missed. These are pedal switches, one for the brake and one for clutch. To be fair I'm kind of glad I found them, as I was a bit confused how to add the brake switch! At least reusing the existing switches should make it easier, no need to mess about with pressure switches in the lines. 

The bit that I couldn't figure out is how they worked. They are a very small travel switch, I couldn't understand how they could be fitted to the pedals and cover the full travel of the pedal. Then I found the original pictures from the MX5;

In both cases, the switches are mounted to the front of the pedals, not the back. So when the pedal is released the switch is pressed, and vice versa. Which makes a whole lot more sense as it means the pedal can move as far as it wants, and the switch can just operate on the first press.

Of course, it now means I need to figure out how to mount those switches. I've taken the standard pedals and turned them upside down, so if I put them back where they are in the pictures then the switches would end up in my heel!! I'll have to figure this one out, should be an interesting challenge!! I'll start with the build manual though, they must have come up with a solution for this. 

Main loom cleanup

Just one more loom to sort now, the main loom. I had a thought about this one. I do still want to strip it down to simplify it, but I'm on dangerous ground with what can be removed. So I'm going to keep things simple. First stage is to strip the wires from the two sides of the engine bay. There are two 'ends' to the loom, one goes through a grommet into the engine bay and runs down the passenger side. There is an equivalent down the drivers side.

Both sets of wires cover two jobs. They both deal with the front lights and some engine connections. What I'm thinking of doing is splitting both sides into their light and engine sets, so there will be four sets of wires in total. I can then trim down the lights that aren't needed, but keep the sensor wiring 100% intact. 

This will give me more freedom in terms of where the lights are in relation to the engine, as well as potentially giving me a chance to tidy up the engine bay. 

There is one thing I need to find out though. The main loom has connections to the dashboard loom, but there is also another connector at the other end of the dashboard loom that I never managed to figure out. Oddly enough, there is a corresponding connector on the main loom as well. Here is the main loom connectors;

and here is the dashboard loom equivalent;

The four connectors on the right of both images are easy, they're the main one. It was the connector on the left that I wasn't sure about, especially as the way it's wired means that it would end up on the far side of the car. 

Let's see what the locostbuilders guys think... once it's back up and running...

Oh, I guess this might be time to give a bit of a view on forums for builders. There are two main options. The first is the Haynes forum itself, http://forums.haynes.co.uk/index.php. This contains a huge amount of information, but as far as I can tell they've been wanting to get rid of it as dead weight. They're not accepting new registrations, and it goes down regularly. Once I can get my password reset I'll be getting on there and downloading some of the build diaries.

The other option is http://www.locostbuilders.co.uk/. This is my go-to place for anything car related. A great bunch of people who know pretty much anything. It's still an active forum, but it's based on old tech and the effort to transfer it to something a bit more up to date would be immense. This also goes down occasionally (database connection error usually) but the admin is just one guy who does work hard to keep things running. It's also the only forum that I actually pay for. It's only £10 a year, but knowing what the admin does to keep it running, and the costs he must have to keep it up, I think it's a tiny amount to pay.

If there are any new builders out there who just happen to find this blog, please join locost builders and help with a contribution to the site. The amount of information you'll get from there is worth far more than £10.

Loom cleanup 3

Last night saw the end of the horrible ignition wires. This is what I had originally;

Such a mess, not one cable was left untouched. They were either cut, spliced, joined to others, or in the case of the pair of yellow wires, left to go off to another device. I didn't want any of that, but I couldn't just cut the connector short. wires at the bottom of the picture go off to the steering column plugs, so the distance between the ignition barrel and the steering column is fixed. I had to rebuild the wires, so I bought some spare wire and some new spade terminals.

The spade terminals were quite simple to work with, but I'm glad I had the right tool. Basically the connector was lightly clamped on to the cable;

Just to hold it in place, then it was clamped properly;

Note the two connector clamps, one to clamp the wires and one to clamp the sleeve. Just for good measure I then tinned the wires with solder to make a good contact. I also needed to flare the back of the curled over section. The latch mechanism in the connector block was for slightly larger terminals so it wasn't working properly for this sized connector. It didn't take much tweaking to get it working though.

The offending wires were cut off, leaving different length wires. This was a good thing, because it meant that the joints weren't all in the same place. This cuts down on bulk as well as potential breaks in the insulation causing short circuits.

Once the new wire was spliced on (linesman splices, nice and secure) they were soldered together then heat shrink sleeving applied. The end result looked like this;

So much better and safer. A quick trial on the ignition barrel;

and everything looks good. The fit was incredibly tight, so much so that a couple of the terminals were pushed out the block. I opened them up a little to make it a bit easier, put them back in the block and they worked fine. Still very tight, but at least they went on to the connectors now.

Loom cleanup 2

Second one done, this is the rear loom. The main parts out of this was related to the rear windscreen, big power cables for the heated screen. It's so long though, I appreciate it needs to get to the rear of the car, across and then back in again, but it is so long!

This is what came out. It did tidy up after this though, a few coils of decent wire that I can reuse elsewhere.

The crimping tool has arrived, and it seems to provide a decently strong connection. Time to rebuild the ignition cable next. I don't know whether to redo the main loom though, there's quite a lot of it and I'm not sure what needs to be removed. It also runs the ECU, engine sensors, all that important stuff. I'll check the connectors to see how many wires can come out.

Loom cleanup

Well, this is where I started;

And this wasn't even the full loom, I'd missed a section at this point!!

First job was to understand my random labelling. It was handwritten on masking tape, and some of it was readable but the majority wasn't. I pinched my wife's label maker and replaced all the labels. At this point I also realised that I'd not labelled everything...

It turns out a lot of the ones I'd not labelled are actually not used. Going back through this blog I was able to see the ones I'd left out, figure out what they did and then mark them appropriately.

Once they were all marked up, it was time to strip out the unwanted parts. First, the instrument loom. The main thing here was the heater and window controls and the power associated with both. The process was to basically start at one end, and work it through by removing the old tape, removing the unwanted wires, then binding up the remaining wires. It worked mostly well, there were a couple of tight spots on the wires that may have been a mistake but overall it's made a decent job;

This has left me with the switch gear (bottom and bottom right) the head unit wires (centre), the instrument cluster (at the top), then on the right there is a ground wire and the handbrake switch coiled up, then the four connectors off to the main loom.

I've tried to keep the removed wires intact, even to the point where I've removed terminals from the plugs. I've had to cut a few wires though, particularly the power and ground leads where they join together. Cut, insulation tape then loom tape, hopefully that should keep things sealed up.

So next is to repeat the process with the rear loom. Oh, and this atrocity;

This is what is left of the ignition barrel wiring after the butchery of 'alarm installation'. There isn't a single wire that hasn't been attacked in some form. And it's all big thick cable. My job will be to cut the whole lot out and replace all the wires. I've bought some 30 amp cable and some 6.3mm spade connectors. Luckily the connector itself is basically a cage for standard female spade connectors, so as long as I can replace the wiring and reterminate the new leads then I can rebuild the connector. That's the plan at least, but it can't go anywhere until I get a crimping tool as I don't appear to have one! That's on order from Ebay, should arrive next week. But I have lots to keep me entertained before then.

To-do list July 2020.

OK, I have the 'build your own sports car on a budget' book, and it's time to go through and see what's left...

• Finish off BR10 cut. It's just a raw end from where I had to cut it off to fit the engine, I need to smooth and cap it.
• Other weld finishing. Just a quick sanity check once the chassis is open. 
• Handbrake mount. I still want to put it under the steering wheel, I like the idea of it being hidden but I've no idea how to do it!
• Gas pedal mounting and linkage.
• Clutch and brake pedal limit stops.
• Seat belt reel mounting. I figured they should be mounted in the inside but they still need to meet all three points without touching the car seat.
• Radiator mount. I don't actually have a radiator yet so that might be a delayed job.
• Roll cage. Still not sure what I'm doing here.
• Exhaust. This will be after the bodywork fitting.
• Oh yeah, bodywork fitting. This needs to include;
• Outriggers on the chassis. 
• Mount points on the chassis.
• Hinges for the front section.
• Trimming the panels to suit.
• Painting the chassis once completed.
• Propshaft resize. I think it needs shortening, but I can't measure it without the diff and engine being in place.
• Fuel tank mounting brackets and straps. 
• Fuel lines.
• Scuttle panel. 
• Windscreen (maybe? Not yet though).
• Brake pipes (solid and flexi).
• Wiring loom. OK, I've put it off for so long, but I think that is the next big job.
• Dashboard and battery mount. 
• Drive it away.

OK, so the construction is very nearly done. I think it's time to look at the wiring loom...

Rear mount done... and tabs

The rear mount is finished, a simple plate to bolt the bush to the gearbox and then a platform to bolt it to the car;

As with most things on this car it's probably overkill, but at least the engine ain't gonna fall out!!

While I was there I also noticed that I'd not welded the two front brake pipe fixings on;

So that's that. The engine will now go in the car. Next job, a to-do list to figure out what the next job is.

Rear engine mount 2

This will be the engine mount as it has been mocked up in Fusion;

The blue section is the new plate that will be welded into the chassis (3mm plate), then the bush will sit on top, then the upper plate (5mm) will be bolted in place.

Unfortunately the drawing shows the issue here. With just blank plates the is a gap that needs to be covered. Normally I'd just add a spacer, but the bush needs the flat surface to sit on, as well as space for the nuts to go on the fixings top and bottom. If I change the angle and highlight the thread, it becomes clear what is happening;

Regardless of the height of the bush, there won't be enough exposed thread top and/or bottom. 

Now I don't want to do any welding on the top plate, if I can keep that as solid 5mm there won't be any leverage imposed on weld joints etc. So drawing that out and cutting it as required is the first job. I think what I'll then do is build up the platform from the chassis, such that the bush still has a flat surface to work on. That gap is 15mm, so I need to make that up.

Time to get cutting and welding...