Brakes, braakes, braaaakes!

[jonclancy]

I picked up a set of 1144 locally for just over £30, but haven't fitted them yet. Looking forward to seeing the difference, though my brakes are much improved now.

I'd look at replacing the brake fluid and re-adjusting the rear drums (as suggested here and worked for me).

But I am starting to wonder if you are having a seal problem in your brake master cylinder...

[Mknight702]

Going to change the brake fluid abnd see what happens (not that I have another trackday planned for this year). I need some more fluid anyway as I had to redo my clutch line as I wore through it by grounding out on some of the lovely smooth roads we have.

[erictharg]

Does sound like moisture in the fluid boiling off. I've not had it happen in my Eleven. I just use regular Dot 4 fluid. Didn't change it for 18 months. Just bled the brakes before Mallory and flushed out some pretty horrid looking stuff, confirming I really should do it more often.
Can only suggest bleeding with new fluid to flush out all the old moisture laden stuff.

Oh - and try not to use the brakes too much!

[Westfield 129]

What brake master cylinder setup are you running? It is possible for the master cylinder to drop pressure without showing a leak.

And, of course, the old problem of old brake fluid moisture boiling off. If you are racing the car, brake bleeding should be done prior to every event, and the fluid changed every year. This is not at all difficult if you have a pressure or vacuum bleeder. Pressure bleeders are relatively inexpensive, and allow the flushing of brake fluid and expulsion of air single handed. No need to pump and then open the bleed screw. This makes flushing or bleeding very easy to accomplish. The Motive Power pressure bleeder runs around $50 USD.

[jonclancy]

Jan said: It is possible for the master cylinder to drop pressure without showing a leak.


I seem to recall, in the distant past of Triumph and Sunbeam ownership, that it was possible for master cylinder seals to distort in the bore. This, specifically, was what I was alluding to.

[Westfield 129]

I spent years working out the braking on my LHD W11. I finally found that installing taper wheel bearings was the single best thing that I ever did to get consistent braking. All of the reports on the Westfield 11s that I read in the UK journals mentioned that the brakes were not very precise, or confidence inspiring. I had just about given up on fixing the brakes, until I found the taper wheel bearings. These made the biggest improvement in the braking, finally giving a consistent pedal.

Once the taper bearings were in, the pedal was more consistent, but the braking would still lack the feel I wanted. I finally installed a new master cylinder (despite the fact that the old cylinder was not leaking at all, and had been rebuilt recently), and that brought everything back into focus. The braking is now consistent, and the pedal pressure confidence inspiring. This is with a single Girling .75 master cylinder. The brakes are firm, the modulation is excellent and precise. I have driven a few other LHD cars, which had the same problems as mine. Installing the wheel bearings and a fresh master cylinder made all the difference. With confidence in the brakes, you can go so much faster...

On my RHD car, I went to a pair of .7 master cylinders to handle the front and rear circuits with the balance bar. This seems to be far and away the best setup if you have one of the RHD chassis, which are punched for twin master cylinders, and Westfield has the bias bar pedal. The cost of conversion is not expensive, but you will probably have to fabricate a couple of new brake lines to separate the braking circuits. The end result is a firm pedal, modulated by pressure, not travel.

[erictharg]

To confirm what Jan says about going to twin master cylinders & bias bar, I've just fitted the Westfield "kit" and it has transformed the feel of the brakes. Only been around the block so far but the feel is great. Much less travel at the pedal. Recommended! Costs about £200 for the master cylinders, pedal and bar, plus a few £'s for reservoirs and new pipes. Don't buy the reservoirs from Westfield. They only stock the AP parts which are about double the cost of the generic items from racing suppliers.
Looking forward to see how they go at the first race on the 23rd.

[adamwilkinson]

I thought you already had them, next it'll be a rear disc conversion...

Our developments are coming on strong, hopefully i'll be out this year to try them

[erictharg]

No - don't need the rear discs now that I've cut down the pedal travel! Who knows - now that I have a decent pedal I might even use the brakes from time to time...

It was also worth doing to have fluid reservoirs you can actually reach. Might encourage me to bleed them more often too.

I though your "development" was taking about 9 months to complete? Trust that one is going to plan!

Saw lots of pics of Ken's new creation at the dinner dance. It's basically an MX5 in drag. He's worried that it will be heavy though...

[adamwilkinson]

3 months left until development 1 completion.

Development 2 is nearing completion and will hopefully be tested soon. Allymally is already running it on his 11 with good results so fingers crossed (its not a power development...)