Poolie520

Hi everyone,
I've noticed recently a burning smell when I get out of the car and walk towards the back of the car to open the boot (trunk).
I did a quick search on here which seemed to point to the diesel particute filter auto cleaning.
Anyway on the way home tonight I put the handbrake on while sat in traffic, I noticed that the handbrake only pulled up about 3 notches before it went really tight. I took the handbreak off but the car didn't roll forward (on a slight slope). I then started moving to keep pace with the slow moving traffic and slowly pulled on the handbrake, I then heard a clunk, next time I came to a stop I pulled the handbrake on and it went 6 or 7 notches as normal. Every now and then the same issue would occur with the handbrake only coming on a few notches and then the clunk sound when I pulled the handbreak whilst driving. It seems like only one side is sticking.
Anyone any ideas how to fix this, is it simply a matter of removing the wheel and making sure the brakes are free from dirt/rust etc.
We've had some pretty bad weather recently and there has been a lot of salt on the roads, could it be a build up of salt/grit
Thanks,
Neil

pauliehcfr

It is very possible that one of the parking brake cables froze due to the cold weather you have been experiencing

Poolie520

Thanks for the reply, to be honest it hasnt been that cold lately and I would have expected the heat build up in the brake would have melted any ice (unless it is some distance away from the brake). I noticed the problem again this morning, it was ok when I first started to drive, I then stopped, put the handbrake on and tried the little test again. Sure enough I could hear the clunk when the handbrake was pulled on whilst driving.
Putting 2+2 together it must be something in the brake drum because it only clunks when pulling the handbrake on when moving.

Has anyone stripped their rear brakes down and done any work on the rear drums.

Thanks,

Neil.

v_therussian

Do you have a manual transmission?

I'm not sure you know that the handbrake in E60 is "by wire" - meaning it can be "reprogrammed" or "reflashed" to address some minor issues.

Your car most likely has the hill-hold option, so when you disengage the handbrake, it is actually supposed to hold until the gas pedal is pressed.

Not sure about the clunk, but could it be related to some rusting maybe? Depending on how loud it is, of course, but it could just be some moisture getting trapped back there and causing the noise to happen when you disengage the handbrake.

Burning smell could be the clutch too, so be careful with that.

Poolie520

The cars a 6 speed manual.
The smell only comes from one side of the car (drivers side - right hand drive).
I gave the car a decent clean the other day and used the pressure washer on the wheel and inside of the arches, I wonder if Ive managed to get water trapped inside.
What is this "reprogramming" you mention, I thought the handbrake was a cable linked to the rear brakes are you saying that it is electronic?
The car does have the hill hold option but this works of the foot brake.
If you have any more info on reprogramming the handbrake I would like to know.

Thanks,

Neil.

v_therussian

AFAIK

1. The handbrake is "electronic" (by-wire). I've had an issue with a loose handbrake lever at one point due to some work having been done on the rear suspension and I had to take the car in to the dealer to have the handbrake re-programmed.

2. Hill hold should work of foot brake and handbrake - again, as far as I know.

Sorry I couldn't help more, buddy.

nsudac

Are you sure the handbrake is "by-wire"?

There's something about it that just doesn't feel by-wire about it to me, although I can't really explain why so I might be wrong

pauliehcfr

There is no "by wire" feature on the handbrake. It is a straight up cable actuated system. It is possible that one of the return springs for the parking brake shoes either broke, came off, or is weak and is not returning the brake shoes to a fully rested position. I had the same problem you are experiencing. I pulled the parking brake apart at the rear wheels and found the return springs on 1 side were installed incorrectly. I switched them around, adjusted the brake and its been fine ever since.

xyzbird

Check rear wheel temperatures (through spokes to brake drum if possible) after driving some distance. Temperature should be warm but if it is burning hot (be carefull not to burn your hand / finger - it could be like touching an electric iron with a wet finger), there is a problem with binding and could be just be one side. This can be caused by inner drum corrosion build up (or even improper set up if it was recently serviced).

Unless you are familiar with brake servicing, you should take to trusted repairer. Replacement of brake pads, shoes, discs and drums is part of BMW servicing sooner or later.

My handbook recommends "To prevent corrosion or an imbalance between the brakes on the right and the left side, apply the handbrake lightly from time to time when coasting to a standstill, provided that it is safe to do so".

You mention that the handbrake lever varies in movement. This suggests that there is a serious problem with varying clearance between a brake shoe and drum and needs attention. Probaly bits coming away and jamming between shoe and drum.

I recall the time I had just returned from a BMW dealer service and noticed the handbrake lever hardly came up at all and after a while the back end of the car started diving up and down. By the time I got home, both rear drums were nearly red hot! I found that rather than the brake shoes being properly adjusted to compensate for wear, slack in the handbrake cables had been taken up which is the incorrect procedure and probably done this way because it was easier. I complained to dealer and he said slacken the cables! I followed the set up in a Haynes Service Manual (it was an E34 at the time) and got it to work properly. Adjustment of the shoes via the pyramid adjusters through an access hole in the drumdiscs is what should have been done to achieve the correct shoe clearances. This allows for expansion and contraction etc (incorrect adjustment causes friction and temperature rise and friction / decreasing clearances will increase as it warms up, and in worse case set fire to your wheel and I have had experience of that as well with another car). Adjustment of cables is rarely required unless they have been over tightened and stretched, or replaced.

I am temporarily driving a courtesy Mini Cooper which has hill start assist where the brakes are held on momentarily. This is the only thing that I can think of as being electronically controlled via some programming. Don't think it is causing your problem.

Poolie520

Thanks for your replies, I get the feeling that its purely something sticking now and then, the spring being worn or broken is a good suggestion and once I can get the car up on a jack and the wheel off I'll have a look at this. This might explain why I get the clunk noise when I pull the handbrake on whilst driving (movement in the drum is enough to free the shoe and return it to its correct position).

I really need to get the wheel off and have a look!

Thanks again for your suggestions.

Neil.