Stubborn warning lights?! and brake bleeding problem

[325ie30]

Hi everyone I'm in a tight spot and need a bit of help from you good people...

I've been fixing up an '87 325i for a few months now and I'm rushing to finish it off and MOT it this week so I can hopefully take it to Santa Pod at the weekend. It's a tall order but I've worked by ass off recently to get it done so I won't give up until I've totally run out of time...

Problems left to deal with:

Warning lights..

- Brake warning light on dash won't go out (the one with the kind of dotted lines around) it's the wear sensor I think. I've fitted new rear pads and the fronts have loads of wear so I don't know why it's on. Any ideas? Someone suggested it might need to be put out with the bmw resetting tool but that seems odd. I tried shorting the sensor too but to no avail.
- Coolant check light on overhead display also won't go out. Guessing this is about coolant level rather than temperature (although the thermostat doesn't work). Again I've tried tricking the coolant level sensor - no luck.

I know I shouldn't really be trying to bodge this as brakes and coolant are important but I just need to get it through an MOT fast and then sort it out properly after. So any suggestions would be extremely appreciated!

The only other thing I need to do is sort the brakes out, have just bled them twice but the pedal in soft and lacks power (I've had 4 previous e30s so know what it should be like). Is it likely to be a problem with the master cylinder/servo? The braking system did get pretty much completely emptied as I removed the rear subframe to do bushes and wheel bearings etc.

I think I'm unlikely to get it all fixed and MOT'd before friday but any help in doing so would be great

Cheers
Rich

[gazza]

i think the pad wear light is a common problem and is the result of a dry joint in the speedo housing try a search on 220 ohm resistor and brianmoooores name and you will find several articles on your problem

for the coolant light check that when it was fitted it is not upside down as sometime it is upside down and may cause the float to give and incorrect reading
as for the brakes start on the side nearest the master cylinder and work away from it ...i use a easy bleed cost about a tenner ish from most motor factors and will allow you to bleed them under pressure ....one last bit do you have a decent bleed pipe that seals correctly on the bleed nipple as it could be letting air back in before you tighten it up .....and when you undo the nipple are you turning too far that may allow air to get past the threads and into the caliper as you have had the master cylinder drained you could have some air in the system and may take a while to bleed this is where the easy bleed works well

[Chris]

Let the brakes sit for a day or so before trying to bleed them again. Sometimes there are just tooo many small bubbles in the system to bleed out and when left to rest for a while these come together to form big 'bleedable' bubbles.

The brake pad wear light isn't a major concern and shouldn't fail the MOT. As stated above, have a search for '220ohm' and 'Brianmoooore' he has sorted that one out for lots of people.

I cant comment on the coolant level light but i would have to guess at a damaged wire somewhere if shorting the sensor didnt help.

Hope you get it sorted.
Chris

[325ie30]

Thanks for your replies guys, all good stuff. Having spoken to a local garage it seems that neither lights are MOT failures so that's a relief. Think I'll follow as much of the wiring as poss to check for damage and inspect the connections etc for a start then check out the state of the resistor joints having found some useful instructions on here for that.
Only concern now for the MOT is getting the brakes sorted, I think there's too much travel in the pedal to be caused by loads of tiny bubbles as it goes very nearly to the floor, so will go and investigate the master cylinder. I can't believe there's air still in the pipes as I've now pumped through over half a big branstons pickle jar of fluid with no air coming through at all. At least there's not that many things it can be, I'll crack on, thanks again

[Brianmoooore]

Does the car have ABS?

[325ie30]

Yes it has ABS.
I re-bled the brakes again tonight - put loads of fluid through to make sure there is definately no air in there. Took it out for a spin to see if it had made it any better - possibly slightly - got back home only to find that the clutch master cylinder had exploded and there was fluid all over the mat and my foot!
Looking increasingly unlikely it'll have an MOT by friday
and still don't know what to do about the blasted brakes. Are you thinking there might be some kind of air-lock in the ABS pump or something Brian?

[Brianmoooore]

If air has managed to get into the inner workings of the ABS pump, then it can be difficult to remove.
The official way involves hooking a BMW dealer machine to the pump which activates the solenoid valves inside it and allows it to be bled. Old_skool_2002 has just successfully hooked up something to do this, but I don't have the details, and he, to say the least, has other problems at the moment.
The other way that is supposed to work is to find some gravel and give the ABS a serious workout, interspersed with more bleeding.

[325ie30]

Sounds interesting. Good knowledge. I'll give it a go once I've got some new clutch cylinder seals in place. So you don't think it's likely to be anything to do with brake master cylinder/servo seals then? This is what one or two other people have suggested. And since the clutch seal just went... I'm unsure of what the symptoms of knackered servo seals would be though, there's no fluid leaking out of the system.

[Brianmoooore]

I've never known a brake seal fail anywhere on an E30, but have changed plenty of clutch cylinders.
Could be because the brake fluid tends to get changed, but I'm sure I come across plenty of E30s still on their original clutch fluid.

[325ie30]

Ok, I've given the ABS a fairly decent workout on gravel, re-bled all corners with lots of fluid and there were only maybe a couple of miniscule air bubbles, brakes still feel the same after. The braking power does seem to be pretty much nearly all there but it's just that you have to push the pedal way far down to get it. When you first begin to brake you can feel where it actually starts to brake and that's at the right point, then there's loads of pedal travel before you get any more power.
Very strange. Very annoying.
Any more ideas anybody? I know it's not the most interesting topic but I really need any help you can give - this is really winding me up!!
Is excessive brake pedal travel an MOT failure or are they just worried about the force?

[murran]

hi, if the brakes pass the effort test on the rollers then its on the tester own disscretion as to whether to fail a long brake pedal. but it is a reson for rejection in the manual but theres no hard and fast rule on it. my pad wear light was on and i couldnt work out why as all the wires to the pads were intact and all the pads had lots of meat on them. my personal fix was to take the bulb out of the dash pod!!!! why mess about with some thing thats built into the car purly for mechanically ignorant drivers. when were not??

[murran]

is there a considerable difference in the brake pedal travel without the servo action? with the engine off pump the brake pedal till all the vacuum has gone and the pedal goes harder. how long is the pedal now? then hold the pedal down with with a moderate amount of force and start the car. the vacuum will build up and the pedal will go down further as the servo helps your own foot effort? if it does the servos working fine. is there any bleed nips on the mastercyl itself to bleed from? also try locating the two pipes from the master cyl at the abs pump itself crack them off a couple of turns while sumones pressing the brake and bleed it there aswell. if that dont work im stumped too!

[325ie30]

Thanks for the suggestions murran.

The servo is definately working but there arn't any bleed nipples on sadly. I tried what you said about bleeding the pipes at the ABS pump - no air there. Also did the same with the pipes coming from the cyclinder that I could get to- also no air Brakes still the same. I'm almost tempted to just chuck it in an MOT and see what they say as there is actually a fair bit of braking power, it's just that it's too far down the travel. It doesn't really feel safe to be fair.
I think the only things left to try are 1 - get a dealer to bleed it with there special ABS pump solenoid opening machine hooked up. 2 - try replacing the master cyclinder. I'm sure I'll get it fixed one way or another, I'll stick a post up here when I do to let people know what the cause was.

In the mean time, any more ideas welcome

[Brianmoooore]

Are you sure that the pull rod across the car behind the heater box is adjusted correctly to take up all the slack in the linkage?

[325ie30]

The linkeage seems to be fine, the long travel in the pedal is not so much 'slack' as just long and soft travel, i.e. there is resistance in the pedal feel.

As the brakes were terrible when I bought the car, something must've happened that I'm unaware of to make them this bad. But what??

If a load of air got into the master cylinder somehow, would it come out with normal bleeding? I have heard meantioning of 'bench bleeding' replacement master cylinders before fitting them, which suggests to me that it's hard to get air out after fitting.
Anyone know how to bench bleed the cylinder?

Do you think it's worth taking it to a BMW specialist garage and saying "bleed my brakes"? I wonder how far they'd go to get it sorted without charging extra. Not very I expect, and they'd probably still charge if they didn't manage to get it any better.

Don't you just hate it when you have to start guessing to fix stuff! I've no idea what to do with it

[325ie30]

I thought I'd let anyone who's interested know how my soft brakes issue was resolved in the end:

ISSUE RECAP:

Soft brake pedal - brakes would bite in usual position but with very little power, then very long pedal travel from there (with a 'damped' feeling) and virtually no increase in braking force until very low down where there was finally enough power to bring the car to a fairly quick halt.

EFFORTS TO FIX:

-Bled brakes many times,
-Checked for leaking and ballooning of pipes etc,
-Gave the ABS a good work-out by slamming the brakes on while driving on gravel to force any air out that might be trapped in the ABS pump, then re-bled.
-Tried the above a few more times,
-Bled from the pipe connections from the master cylinder, also from the connection to and from the ABS pump,
-Adjusted the brake pedal height

WHAT FIXED IT:

I was expecting at this point that it was the master cylinder at fault. I had a doner car but it didn't have ABS so was the wrong type of master cylinder. So I thought that before I forked out for another cylinder I may as well try swapping in the servo from the doner car as I knew it worked fine (although I'd been told it was unlikely to be a servo problem). Hey-Presto it worked! Very relieved to have the brakes sorted, been a bit of a pain to say the least.

Not suggesting people go swapping servos about for every soft brake pedal! Go through the motions first of course but lesson learned - servos do go wrong.