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Brake problems...

...a bit of background first.

I've recently been giving the brakes on my Alfa 146 2.0 some reasonably large disturbance. So far, I've replaced all brakepipes to the rear due to corrosion, a rear caliper, a flexihose, had the brake compensation valve out and completely drained, refilled and bled the system.

Now to my problem - I just cannot achieve a decent amount of firmness....on the brake pedal that is. I've tried everything I can think of. Ezibleeds, bleeding the calipers in various orders, bleeding them all at once, raising either end of the car, not pumping the pedal, pumping the pedal - with or without the engine off, leaving the brake pedal depressed over night, jumping up and down in the car to actuate the compensation valve. Nothing seems to have worked.

I have had some success. I can even get it rock hard with the engine off and the pedal has gone from having no effect whatsoever to what I have now, piss poor brakes and a spongy pedal as soon as I fire her up.

My current thoughts and questions are these...

I've been round with a hose clamp on all the flexipipes and possibly seem to get a slightly more positive response from the pedal when I've clamped one, but none in particular are jumping out at me. I'm going to replace them all anyway I think to be sure, but what's the likely hood of their net affect giving me the problems I'm having. Also, would there be any issue with replacing flexihose with brake pipe, as there's at least two more flexihoses in the circuit somewhere, other than the ones that end up at the calipers.

Other than that, I'm now beginning to doubt that I reconnected the brake pipes to the compensation valve in the right order. I'm 99% sure that I did, but I'm begining to wonder if it would cause this problem.

it's worth mentioning that before I started the work, the brakes only had an RBT efficiency of 47%, although they did feel much better than they do now.

Apologies for the essay

MikeL

Reply to
MikeL
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Does the car have ABS?

Also could be the master cylinder starting to fail (the extra travel when bleeding the brakes can be enough to cause them to fail)

Reply to
M Cuthill

Forgot to add, yes it has ABS. I've was also very careful not to start jumping up and down on the pedal when it had no fluid in, thus hopefully avoiding buggering the seals.

I probably should also have mentioned that I've checked that I've got no leaks either.

ta

Reply to
MikeL

Most likely you've got some air into the ABS modulator. Typical symptoms are you can get a good solid pedal with the engine not running, but as soon you start the engine and get a bit servo assistance, the pedal will disappear to the floor. Only option is to get the ABS activated while bleeding, which requires diagnostic kit.

Reply to
Moray Cuthill

"Moray Cuthill cuthill_at_v21.me.uk>" >> Does the car have ABS?

Hmm...interesting. Certainly something that I'd not thought of. It's not mentioned in the workshop manual I have for the car, but I bow to your greater knowledge.

Is there anyway I could short an ABS sensor or something to avoid giving the Stealership cash when I've already done all the hard work for them?

Reply to
MikeL

It all depends on how good the brakes are at the moment. I have known people to bleed the brakes, find somewhere with little traction (gravel is good), work the ABS a few times, and rebleed them, but I've not personally tried that approach.

It doesn't have to go back to a dealers. You should be able to find a local garage with suitable diagnostic equipment, that would do the job for a lot less than a dealer.

Reply to
M Cuthill

That's a cunning plan which I will try out. I'll let you know how it goes.

Regarding the garage, as much as I am sure there are great places out there, I have real trouble finding them. Only once in 9 years of motoring have I driven away from a garage satisfied that the job was done well. Unfortuantly, said garage is 30+ miles away, extreamly busy and in the middle of nowhere, thus they're a bit inconvient.

I prefer doing things myself too TBH ...

Reply to
MikeL

I asked my dealers what the procedure was to bleed the ABS pump on a Daewoo and if it needs connecting to diagnostics. He said as long as there is no ABS fault you can drive the car for a few hundred yards so it goes through the ABS self test phase and then park up but don't switch off the engine as this keeps the ABS valves (or whatever) open so it can be bled. But I suppose there is many different kinds of abs systems which will require different methods.

Reply to
redwood

Well I finally got round to trying these out. Unfortunatly it didn't help. Finally got it sorted though by getting someone to stamp on the brake pedal whilst the engine was running before I undid the bleed nipples.

Many thanks all.

Reply to
MikeL

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