Brakes

Brake pipes and heatsheilding

I’ve had a few more hours in the barn today as our big house build is complete and the decoration DIY nears completion. I’m hoping this becomes more frequent in the next few months but we’ll see.

I’ve been working on getting the brake pipes connected up back to the master cylinder and protected from the heat that the exhausts will give off.  First off has been getting the pipes unwound from their temporary coil (left that way 2 years or so ago!) and fixed to bulkhead and routed to the master servo. With a bit of trial and error working out how tight you had to go to get a rivnut in set correctly, rather than breaking the mandrel (not so tight) the pipes are now in place.

Not so pretty brake lines

Not so pretty brake lines

They’re not great by any means but at least they are fixed in place now.  Next up was how to hide the mess and shield them from the heat from the exhausts that will exit just under the servo and by the lines. There are some great examples on various other sites including wrapping them with thermal tape and a fantastically nicely made shield (here) with thermo-thing calculations to go with it!  I like the later option, but knowing I’m a complete ameture at this I reality checked myself and started hunting for some thermal sheeting which I can create a more simple shield from.  After much hunting around I found something called “Nimbus GII 2 Layer Heat Shield” material that seemed like it may do the job.  Being aluminum and made for the job of holding the heat back it seemed like it should be flexible enough to work with so I thought I’d give it a go.  One quick order with Merlin Motorsports for 2 300mm x 600mm sheets and I had the necessary bits.  With a an hour or so set aside for bodging a cardboard template and then another couple for scratching my head and cutting the sheets down to shape and size I think it may end up working, which is a nice surprise!

The two parts are all covered in masking tape at the moment to protect the paintwork and check the fitting, but it’s initially looking good.  More rivnuts have been sunk to allow the pipe shield to be attached to the engine bay / wheel arch wall and I need to find some nice looking brackets to help mount the the servo shield plus some rubber edging to finish the panels off.  Lastly, a few holes will be made in the leading edges of the shield to allow more air to flow over and out the exit vents to help with cooling but they should be ready for fitting very soon 🙂

Build time: Somewhere around 185 hours in the garage but too many on the Internet researching…

A good day..

After a few weeks of struggling with the back end things have came together. The extractor has been ground out, a new hole tapped and the handbrake assembly mounted.  One tip I picked up was that it’s far simpler to put the calliper mounting bolts in first before the assembly goes on as it’s too tight for a couple of the  bolts later…

Calliper mounting bolts in first

Calliper mounting bolts in first

An issue with the callipers mounting bolts was quickly sorted too, the smaller guide pins were in the wrong hole! Once swapped round everything went as it should and now both axles are in along with handbrake assemblies, brake disks and calliper mounts.

The last bit of good news is that my wheels are ready for delivery and should be turning up next Friday! Happy days indeed!

 

Build time: 46 hours

Brake pipe fitting…

What a lovely Easter break it’s been! I’ve just spent 10 hours in the shed tinkering and couldn’t be happier!

I started fitting the copper pipes for the brake lines properly and after a few head scratching moments have them all pretty much in place.

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The rear ones are tied with cable ties and proper clips. I did these after the front set so they’re a bit neater.

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I think from the pics you can easily spot my first pipe. After an attempt to bend it around all corners I buggered up most measurements so gave up trying. Discarding the socket I used to shape the corners and my nifty bending tool I found that hands and fingers generally worked the best.

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I’ve not gone with the traditional route for the front passenger side pipe – I’m not sure why as I thought I’d read the instructions correctly a few times and looked at other examples many many times before committing. On the evening I drilled the holes I had another look at some other blogs and found that I should have taken the pipe across the flat.  Hopefully what I’ve done won’t cause any issues with the remaining pipe length when connecting it up or when bleeding or filling the system as I think that peak could be an ideal air trap!  Fingers crossed it will be OK, otherwise I’ll have to lower it some how…

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Anyway all pipes are in place I think. Just the rear axles to put in now as I also managed to calculate my shim packs for the rear hubs. This would have been tackled too if it wasn’t for some missing bolts and tapered washers. It could be I’ve misplaced them but I don’t think I have so I was a little bit peeved until I realised that I’d actually made some good progress.

I’ve ordered said bolts from Namrick but need to work out if I can taper a washer myself, otherwise I need this from Dax and they can be difficult to get hold of quickly…

 

Build time so far: 39 hours

Drilling the Chassis! Gulp

I went up to the garage today to continue a job I’d started last week – setting up the rear alignment and getting started with the rear brake build.  last week I’d found that whilst I’d bought the necessary iron square tubing I didn’t have any fishing wire (or anything similar) to extend out the rear hub lines for checking the measurements at the front so that halted things early.

During the following week I made sure that I picked up some fishing wire and few other thing that I knew I needed so that I’d be able to make some progress this Friday so I was quite excited as I cycled (crawled) up the very long hill towards my lockup with the box of newly delivered bits on the back of my bike only to have all my plans scuppered within a few minutes after opening the box to find that the fishing wire was the only thing that I hadn’t packed!  Argh! Stupid Me!

After procrastinating trying to think of other jobs todo I finally stripped down some of the mobility scooter that I’ve bought as a side-project for a kids-cobra / tot-rod and felt a bit better.  This activity didn’t last long enough though so I had to find a “real” job and I finally settled back on looking at the front brake pipes. The next natural job for those is drilling the holes for the clip mounts – these would be the first holes to be drilled in to the chassis so I wasn’t to sure what to expect and how hard it would be but I’m pleased to say it all was a fine – slightly disappointing really as there was no drama.

I had expected the chassis to be really hard steel but a fine 2 or 3mm drill bit went through quite happily whilst drilling fairly slowly. I then opened up the starter hole with a wider drill bit however I suspect that I could have just skipped the starter hole as the wider bit did stick a couple of times.

All in all, quite a few of the holes made for the copper pipework at the front of the chassis just need to fit the plastic mounting clips but before I do this I want to get a hold of some waxoyl to back fill and ensure these clips don’t get a chance to let water in.

Build time so far: 29 hours

Front Brakes On

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Only a few hours today in the lockup after a break of 3 weeks or so but the good news is the guys on the cobra forum came through and after swapping the pads around so they clip to the piston both sides are now done.

One thing that made me question the assembly again were different coloured caps on the brake pipe connections on each caliper – red on the passengers side and yellow on the drivers side. In the end I decided that the difference wasn’t relevant to this part of the build but suspect that I’ll come across some explanation in the months that come.

Next jobs on the list, set up the rear geometry and do the final drive assembly, oh and fit the copper brake pipes…

Off to B&Q this weekend to pickup some steal square bar…

Build time so far: 23 hours…

Front brakes…

I had a go at building the front brakes this afternoon.

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Initially I was quite pleased but now I have a feeling that something isn’t as it should be so the passenger side no longer has the caliper mouned.

The caliper carriers have been bolted and red loctite’d to the front uprights after popping the discs in place. The’re was quite a bit of confusion in my head about which disc were the front ones as the discs delivered with the kit are of two different thicknesses and the carriers are also of two different sizes. Obviously one pair for the front and one for the rear. After matching up holes and carrier clearances it appears that the larger carriers and thicker discs belong at the front.

Before the assembly the hub would turn without too much effort but now the calipers are in place you can hardley budge it. It’s as if the brakes are already applied.  The unit went on to the carrier with only a little bit of coaxing before the guide pins were inserted but there’s absolutuely no clearance of the disc itself which is a little worrying.

I also have a feeling the pads should be swapped around and the metal bracket clipped to the caliper piston rather than the caluper so it pulls back as the brakes are released, also I suspect I don’t quite need as much copper slip as I’ve coated the one above with?

More questions for the knowledgeable folks on the cobra forum and I expext I’ll be redoing this work next week. At the end of the day it’s all good practice!

Build time so far: 20 hours…