Colapsed Hose or Hoses

Maybe not. A new neighbor gal asked me to look at the brakes on her Bugeye Sprite. She said when she starts out early in the day the brakes act fine, but very quickly the pedal gets hard and the braking is very poor. I suspected something causing the brakes to not release and sure enough when she pulled into my shop the wheels were very tight. i spent some time cleaning and deglasing the brake shoes and drums. Assured myself the wheel cylinders were working at all corners and that there was no leaks. I put things back together and adjusted the brakes fairly loosely and was hopeful that I had solved the problem. All the wheels turned freely. But after only a few applications of the brake pedal ALL wheels got somewhat tight. The wheel cylinders look like they are fairly new and the the hoses, (one back, two front) don't look that old either. Should I immediately suspect the Master Cylinder. It seems with only a few applications of the brake pedal, the brakes on all the wheels don't want to completely release. Yet let it set a few hours and the wheels are free again. Thanks for the help.

Sounds like old bad hoses to me Vette ?

Does the master cylinder have a vented cap?

Sounds like a master cylinder problem. For some reason the piston is not returning far enough to allow fluid to return to reservoir, holding pressure in all the lines. One way to test this is to drive until they feel locked up. Stop vehicle and crack open the easiest to access brake bleeder(usually a front wheel cylinder). Close bleeder, drive vehicle and see if ALL brakes are now free. If so, problem is at the master. If the length of the pushrod is adjustable, shorten it some and retest. This problem also occurs on the 100 when someone misadjusts the brake pedal pushrod.

EDIT: Just checked Moss website. It appears the pushrod for the Bugeye is adjustable.

We have returned from watching the Mille Miglia in our Healey 100 and had the sef same issue, whereby the pedal would stiffen up etc.
I checked the free movement of the front brake cylinders and all was fine.
Continued backing off the master cylinder to help the problem.
On return to the UK, I fitted new front flexible pipes. Albeit the car wasd fitted with recent Aeroquip pipes.

Issue solved,

I figure one of the pipes was twisted, allowing fluid past under braking pressure, but not allowing it to return.

An easy fix, hope this helps.

Thanks for ideas everyone. I might not get to work on it today but I'll do all the checks you've suggested.

I'd suspect the master cylinder. Its the dual cylinder like the MGA right? If its been changed to silicone fluid that will cause the main rubber seal to swell slightly and block that return hole, or if its had the wrong fluid in it causing the seals to swell , the result will be the same as the main piston not returning all the way due to crap etc.

YEP!!!!! And replace hoses to be safe. Use only Castrol LMA fluid.
Wheelguy

wheelguy said:

...Use only Castrol LMA fluid. Wheelguy

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FWIW, we put LMA in our BN2's freshly-overhauled system--new everything--and it worked fine until the car sat for a couple years while my father was ill. It turned to gel.

Bob_Spidell said:

FWIW, we put LMA in our BN2's freshly-overhauled system--new everything--and it worked fine until the car sat for a couple years while my father was ill. It turned to gel.

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I've been using NAPA DOT4 for 10 years with no ill effects. I like it because it comes in quarts.

steveg said:

I've been using NAPA DOT4 for 10 years with no ill effects. I like it because it comes in quarts.

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After the debacle with Castrol we re-overhauled the system and filled it with Pentosin DoT4 (I believe this is the preferred brew for Bimmers?). No problems after several years (most of the time the car sits).

Just an Update on the Bugeye brakes. It turns out that the master cylinder was not adjusted properly. It has adjustable push rods as was suggested previously and it is like an MGA. The push rods for the brakes and the clutch were adjusted up with no play in them at all. I loosened the rods just a smidgen and the brakes work fine. But now also the brake shoes need renewed because they drove it so much with dragging brakes they are worn to a thread. Also the drums are out of round so probably new drums as well. Thanks for the help. Dave.