Weekend update (exhaust and handbrake fix)

 Well, more of a midweek update as I didn't really get much done on the weekend. It was the kit car show on Saturday, a great turn out and it felt like more than previous years which is always a good sign. Lots of cars for sale though, either it was the same as previous years and I've never really paid attention, or there are genuinely more people selling up. 

So that was my Saturday, then a bit of slab work kept me busy in the afternoon. Well, technically that same work kept me busy Sunday because I managed to drop a slab on my foot and not be able to do anything too heavy on Sunday!

Anyway, enough of that for now, on to the exhaust. As I may have mentioned before, the headers wouldn't come off without me disconnecting the rest of the exhaust, so that's what I did yesterday (Tuesday). Once all the gaskets and sealants were in place I could bolt it all back up. For the most part it worked well, but now I can see how rigid it is when bolted up I do have my doubts on how long it will survive without a flexi section. It's not difficult to put a flexi in place, the layout does accommodate one inside the engine bay but it would mean two more joints. I'll add that to the post-IVA list maybe. 

In the meantime, tonight's exercise will be the handbrake cable. The plan will be to make the cable as loose as possible, then mark where it hits the balance bracket. I'll then make a loop in the cable and clamp one of the ferrules on to it. Two would be more secure but there's not enough room, using just one ferrule means I can squeeze it inside the bracket and not compromise any gaps.

That should leave me with as much flexibility to tighten it up as possible, after all the cables will only stretch over time. They're not going to shrink. 

It does mean that the self adjustment may not work as that relies on the ratchet mechanism working in the caliper. However even on the stock MX5's that auto adjustment rarely works, and most of 'the internet' manually adjust the calipers directly before adjusting the cable. Not a difficult process, just 'old school'. 

And of course, there is something in the IVA manual about it;

A parking brake lever, actuating linkage, cable or associated component must not be obstructed in its travel nor foul parts of the vehicle 

And;

Parking brake reserve travel and locking positions are required to allow components such as brake cables to stretch without diminishing park brake performance.

This could be a fail point if it's judged to be too close. The other option I've been thinking about is a spacer on the handbrake cables. This is where they're currently mounted;

It's a simple bracket, reinforced by the folds. If I use an appropriately cut and drilled piece of steel, I can bring those back 20-25mm or so. A couple of tacks to hold it in place and that would be fine. And just typing I think I'll do that anyway. As with everything on this car, I'm always thinking about keeping very clear of IVA rules. Moving it back that far will mean the cable can travel as much as it wants (the caliper itself will stop it operating any further). 

And I've just realised there's an issue with that. The cables use clips to retain them in the hole. If I move the hole I still need to be able to retain the cables. 

(quick dive into the garage...)

A quick measurement of the bracket and the cable gives me some options. The widest part of the cable is 25mm, that goes on the outside. There is then 13mm on the narrow part and 19.5mm on the last part. So whatever I use for the bracket has to accommodate a 20mm hole. In terms of thickness I'd estimate 2mm maximum, which is fortunate as most of my metalwork is also 2mm max!

The bracket is 30mm deep so that would be good for the 25mm square section, maybe with a bit of profiling on each side. For the clips I would simply cut out an access hole above both cables, while that might make the cable clips difficult to remove at least I'd be able to get them in there in the first place. Having said that, this extra bracket needs to resist compression forces rather than tension, so I'm wondering whether bolting it in place would make it simpler. Then at least the whole unit could be removed with the cables when it came to unclipping them. It would also mean not having to weld anything near my newly upholstered seats. There's enough room for an M8 bolt with washers so no danger of it being weak. 

That's that then, a small bracket to cut and fix, then the whole adjustment issue goes away. And to think, a lot of this is caused by wanting an 'invisible' handbrake! I was keeping an eye out at the kit car show for other cars that have no visible handbrake, I couldn't see anything like what I'm doing. The closest I could find was on a couple of trikes where the handbrake was a pull handle. I've seen that before where it locks in position and it's twisted to release. That was still visible though, less intrusive than a handbrake but still not 'clean' like I want it. I should have looked for early Caterhams, although just checking the site plan there wasn't a Caterham stand. 

Oh, last thought before I post this. This whole process will move the sleeves back an inch or so, but the brackets on the cable are fixed. They should go into welded brackets before heading to the calipers, I may have to review that routing. It's not like the speedo cable that has to be gently curved into position, but I still don't want them pushed into unusual shapes on their way to the calipers. I could always cross them over to reduce the bend tightness, I'll see what I need to do once the bracket is done. 

(Later that day). Well, that plan failed. By the time I'd cut away enough metal to fit in the gap, with the correct holes and big enough slots for the clips, I ended up with such a weakened part that it wouldn't have worked! I think the failure was right at the beginning though, trying to cut it from 25mm RHS. It might have been rigid, but having to remove three sides from a four sided tube was never going to work. 

So the new plan will be a metal plate bolted to the front of the same bar, with a reinforcement at the bottom against the old bracket. The same approach though, fix the cables to the plate then bolt the plate to the car.

One thing I did see was that crossing the cables won't make much difference, the next bracket isn't very far away so it won't move by a significant amount. 

(Update from the 9th). After the first failure, I went uber simple and just used a drilled plate.

As mentioned I could only use 2mm because of the fixing clips, but it's plenty strong enough. I stayed with the idea of clipping the cables in place first then bolting it to the car, with three bolts going to the original cross member and the original fixing plate. The last picture shows a much better 'home' position for the plate, with plenty of space for adjustment and slack on the cables. Just one last job to do here, fix the front cable. That needs the handbrake in it's final position, which needs the JB weld alteration done to get rid of the sharp edge.