Still havent fixed the brakes...

woods - you gonna be about later ontoday? am goin 2 visit my friend at surrey uni, may be takin him down a green lane or two

boydy1989 said:

woods - you gonna be about later ontoday? am goin 2 visit my friend at surrey uni, may be takin him down a green lane or two

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chances are he aint gonna be online till this evening. I can give him a buzz if you like

probably not worth it, it was mainly to collect the master cylinder but im not sure how long ill be in guildford for. Let him know if you want though!

Ta!

You have a MP boydy.

woods767 said:

You have a MP boydy.

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Fingers crossed for Boris Johnson!

Doh.

Hey woods - did you manage to fix ur brakes in the end? I've got exactly the same problem with my Def 110.

I've changed all pads and shoes but still no joy.

Has been suggested to try changing the master cylinder, and was wondering if that's what you had to do in the end or did bleeding the system work?

Changed the servo unit and master cylinder, one of those two did the trick. Befor you do that, ajust your drum brakes if you have them, it makes a masive improvment alone.

Check your vacume pump for pressure befor you change the servo unit, if its not pulling a vacume, its most likedly the vacume pump.

What esactly is wrong?

The pedal goes quite far and soft whilst the engine is running, but pumping it a few times brings it back to normal feel.

I've adjusted the rear drums a couple of times now - tightened the adjuster up completely and then slackened it off by one notch.

I've followed the Haynes manual for testing the servo unit (press brake pedal whilst engine is off, start engine and you feel a slight drop in pedal pressure) and it checks out, so I guess it must be the master cylinder.

I was just about to pop out and get a one-man bleed kit and purge the system. Someone else suggested clamping each hose in turn and testing the pedal travel to try and find which end is causing the problem.

Sounds just like mine, the servo unit test checked out fine too, but it was still causing isuses somehow so dont rule it out. Those brake bleeding kits are good, i bought one too and its great.

Thanks for this, I've got the exact same problem on my 1988 90 with rear drum brakes. Ho Hum... At least I know what worked for you...

Other thing i changed a while back was the slave cylinders in the drums at the back as they were leeking. Watch out for that too if its the drums that are giving you hassle.

Ah yes will check that. I thought there might be a leak of some sort from inside one of the back wheels (but I'm not getting through any brake fluid, same as you) the last time I happened to look underneath on a dry day.

Ok, I've changed out the Master Cylinder and the Servo unit, and also changed the rear cylinder with the slight leak.

Pumped new fluid through the whole system as the old reservoir had quite a bit of junk in it - did notice that in one leg of the pipework the fluid was white and milky, like it was contaminated.

Anyway, did all this, bled it completely, readjusted the rear drums, and it's better but the pedal still travels a bit, and you can still pump it solid with a few presses. Once it's up the brakes are brilliant, but it soon goes again.

Also, if you rest your foot lightly on the pedal, you can feel it fading beneath your foot.

Don't get me wrong, it is better but I think that may be down to the change of fluid more than anything.

Any more ideas? The only thing left I guess is the vacuum pump.

darkcyde said:

the old reservoir had quite a bit of junk in it - did notice that in one leg of the pipework the fluid was white and milky, like it was contaminated.

Anyway, did all this, bled it completely, readjusted the rear drums, and it's better but the pedal still travels a bit, and you can still pump it solid with a few presses. Once it's up the brakes are brilliant, but it soon goes again.

Also, if you rest your foot lightly on the pedal, you can feel it fading beneath your foot.

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Sounds to me like you've got a pipe with a hole in it or corrosion pitting enough that it's letting air in .. the milky white colour suggests this, and the pedal going soft means it's definitely got air/some contaminant in it or it's leaking out.

The leg that had the white stuff in is probably the main culprit, so I'd check this thoroughly, every inch of it, maybe (for the price) just replace it ... then check/replace each other leg as and when you can.

Get someone (you) to check the brake lines while someone else pumps the brake pedal hard, repeatedly ... the leak might be more easily spotted this way .. and someone else checking the fluid levels.

Check your flexible hoses too - one of them might be bulging under pressure.