I have a rather strange problem that has suddenly developed with the brakes of my 1966 series 3 Elan. The car was fine when I put it away for winter last year, but is now suffering from a complete loss of hydraulic brake pressure after it has been standing for a while. One pump of the brake pedal brings back most of the pressure, and a second pump makes the brake pedal feel as hard as it should be ... and there isn't a noticeable loss of pressure while the pedal is held down ... no pedal creep. But leave the car for a while and the brake pedal then goes straight to the floor again with no pressure ... until it is pumped again.

Because I have nowhere to work on the car I took it to a classic car specialist in Poole. When bleeding the brakes made no difference he decided it must be the servo, so he by-passed it. That seemed to work OK but then when I left the car standing overnight the brake pressure disappeared again !

I'll have to take it back to the garage, but I don't want to waste more money paying him to scratch his head ... so if anyone can offer suggestions I'd be very grateful ! maybe someone has seen this problem before ?

Good afternoon Ken and welcome to the forum,

When i had brake problems with one of my Elans a couple of years ago, it turned out to be master cylinder rubbers. You did not say that you were losing fluid, so i assume not.

After the winter layup, i just started the car and drove off. Where i am situated, i dont have to brake at all, until i get to the end of the lane where there is a T junction onto another quiet lane. Fortunately, there was nothing coming, as on pressing the brake pedal, it went straight to the floor, no pressure and no brakes! Managed to steer round the bend, and after mopping myself up, drove home very carefully. On inspection, there was no fluid in the reservoir. Well i looked everywhere, but blowed if i could see where it had leaked out.

So i replaced the master cylinder rubbers, and all has been okay since. What i did not realise, until all the old brake fluid had been purged from the system and renewed with fresh, was the deterioration in the cars ability to stop. I always remember this car being able to stop on a sixpence, but in recent years the brakes had faded, due to me not changing the fluid for about 5 years.

Well Ken, i would think your mans next job, would be to replace the master rubbers, and then to bleed completely.

Good luck.

Leslie

Sounds like master cylinder rubbers to me as well. But it raises a question...when were the brakes last fully overhauled? If you don't know, and the master cylinder has gone, I would go through the callipers, the flexi hoses and the clutch hydraulics as well.

Mark

I'd agree master cylinder. Could be the seal between the cylinder and the reservoir. Do your quick pumps to build up pressure until firm, then put light steady pressure on the brakes and if it goes slowly to the floor, you've found your problem. Dan

Many thanks all for taking the trouble to respond so quickly ! I overhauled the brakes myself in 1991 ... calipers replaced with anodised units ... brake lines renewed ... steel braided flexible hoses fitted ... EBC pads fitted ... servo refurbished / overhauled ... master cylinder overhauled ... I even took the foot pedal assembly apart and had it all powder coated. Clutch master & slave cylinders overhauled, and both systems filled with silicone fluid as I'd been told that's hydrophobic so won't get contaminated and degrade ... also better for seals. Since then the car has done a total of 12,000 miles and been fine, if anything the brakes were a little too fierce but I got used to braking with just my big toe (preferring to drive bare foot anyway) otherwise the car would stop on a sixpence / dime to the general astonishment of all and sundry. I've now recently had the same experience as Leslie of approaching a T-junction and hitting the brakes only for nothing to happen as the pedal reaches the floor. Like Leslie I was fortunate enough for there to be no traffic crossing the junction at the time ... but a change of underwear was nearly needed. I've tried Dan's method of testing the master cylinder but if the pedal is creeping under light pressure then I can't detect it. I guess I'll have to fork out for the master cyclinder to be overhauled, gritting my teeth at having to pay for such a simple job to be done by someone else due to lack of anywhere to do the job myself where I now live ... block of flats on a hill side with nowhere nearby level to stand the car on. Thanks again for all the helpful comments, much appreciated.

Ken,

I have sent you a PM.

Leslie

Ken,

You don't need a level surface to stand the car on. To rebuild your master cylinder, all you need is a kitchen table.

Re-building the master cylinder isn't the challenge, it's bleeding the brakes afterwards! My garage is too small to contemplate scrabbling around underneath the car, and there's a steep slope immediately outside so nowhere to stand the car outside. Anyway Leslie from this forum has come up trumps with the offer of a flat space in Bournemouth & a helping hand, so hopefully (weather permitting) the problem will soon be solved! Many thanks again to everyone who chipped in with suggestions, great bunch.

Ken

FWIW, my own experience with MC rebuilds is similar to your description.

Year: 1978
Car: 1965 VW

Problem: Decay of braking performance.

First solution: Rebuild MC. As a college student, the $25 for a rebuilt MC seemed too dear compared to maybe $7 for a kit.

Problem: It worked, kind of, from home in Massachusetts to school in Baltimore. After that, soft pedal. Bleeding would restore a nice pedal. On the way home for Thanksgiving with a passenger, I noticed that after an initial stab, the pedal softened. About five pumps per toll booth to reach a stop, lots of these on the 450 miles to home and a garage.

I think I did a pretty good job of hiding the fact that the car had no useful braking capability from my passenger for the duration of the journey.

Disassembly showed no leaks. But after spending the dear $25 on the rebuilt MC, the problem disappeared forever. My theory is that if you don't hone the cylinder when rebuilding, air figures out a way in through the back of the cylinder.