Badges and clutch stop

 The first task from this weekend was a clutch stop to prevent the pedal from moving too far. The problem is I didn't appreciate how much travel I'd put into the clutch pedal! It's not surprising that the clutch pedal can push it too far. But it meant that to add a physical stop would have had the bolt mounted either on the cylinder itself or where a brake line lives. Although looking at the pictures using the upper mounting bolt may be an option;

I may look at that during the week, it's only just occurred to me. I was looking at drilling a new hole and dismissed the idea.

In any case, what I did do was add a sleeve to the pushrod to limit the travel there. 

This works very effectively and is quite a hard stop on the pedal. However it's effectively pressing against the master cylinder and I'm wary whether that would be considered an issue at the retest.

This is the slave cylinder at rest;

And at full travel with the stop in place;

If I compare that to with it taken out;

It does really help with the movement but it's not strictly needed to get past the test. So it stays off for now.

I can actually see the upper fixing bolt of the MC in a different photo;

Access is tight but I could figure out a decent bolt length pretty easily. I'll keep that as option two.

Given that I have almost nothing to do on the car, I thought I'd look at a bit of decoration. On with the 3D printer;

It was a bit of a faff getting it from text to 3D lettering but I got there in the end. It looks nice on the car as well;

The size looks good and the lettering suits the car, the only issue is the colour. It needs to be metallic at least, if not chrome. I'll see if I can find some chrome (ish) paint and give it a spray. 

This will sit with the boot, dashcam, phone mount and all the other bits and pieces to be added post-IVA.

Lastly, I gave the corner weights a go. It wasn't particularly accurate but when I started I could see the left hand side was 30Kg lighter than the right. That would be enough to throw off braking efforts. A few tweaks to the spring platforms got it to about 5Kg difference. Although I then remeasured the indicator height and they're about 10mm different either side. It probably won't be noticeable but I daren't do any more tweaking with springs. A quick drive down the road showed that both wheels locked up at the same time which is pretty much perfect. I have also dropped the tyre PSI down to 18 so all of that is basically giving the car the best chance for braking efforts. If it doesn't pass with all that then it's major surgery time, either a different master cylinder (and therefore different plumbing) or even worse would be a brake booster which would need some major mechanical changes. 

On the subject of brake booster, I did speak to someone on LCB who used the MX5 brake booster. I was trying to figure out how that would be possible, but then after seeing a pic I realised what was happening;

His car uses a lot more of the pedal box from the MX5, including many parts that I discarded. This way round means the pedals come down from above, and all the mechanical parts work the same way as the MX5. Most importantly this keeps clearance for the brake booster. 

I can't really follow this approach as my fuse box lives where all this would go, but it does explain why he was able to retain the brake booster. 

Still, just driving my car a short distance shows the brakes are effective, so I'm still hopeful an unboosted version will suffice. I now know of at least one car that managed to get on the road without the booster;

This is from another car on LCB which shows the same MC that I'm using. 

Just for reference (and I have a feeling I've already posted it somewhere), I currently have;

134Kg nearside front

194Kg offside front

91Kg nearside rear

96Kg offside rear

For a total braking effort of 515Kg. From a design weight of 770Kg that gives me an efficiency of 66.88%, which is a pass. The new design weight of 400Kg + 500KG (900Kg total) that would only be a 57% efficiency.

To pass I need to get it to 60% efficiency, which is 900Kg/60%, or 540Kg. In other words I need to gain 25Kg of braking force. That really isn't much to be honest, the new discs and pads have an improved surface area which should suffice. In theory because the front wheels locked then the brake effort there is more about traction than brake effort, but with a dry day and reduced tyre pressures I should get more out of them. At the very least both sides should be reasonably even.

Interestingly just looking at the braking efforts again the parking brake gave 272Kg on the rear, whereas the service brake was only 187Kg. That does suggest the mechanical leverage given by the master cylinder is less than the handbrake, given both act on the same brake pads. Again, if I can get a little more on the rear that will also help. 

I need to take my mind off the brakes though, I have done literally everything possible. All the other issues were well defined and have a nice big tick next to them. The only thing I really need to focus on is the drive back to Bristol. More specifically, the weather at the time of the drive! If it's dry then great, if it's sunny then even better. If it looks like rain I'm going to need to do some prep work. 

Oh yeah, and I cleaned the car! Only a quick wipe down with soapy water but it really made it look good.