Technical Grinding noise rear left wheel - brake issue?

[capers626]

Hi all,

I've been having an issue with an intermittent grinding noise coming (only) from the rear left wheel of my 1993 Fiat Uno, which varies according to speed of rotation. This occurs when driving along but not all the time and feels like a drag effect without applying the brakes. I thought it was due to a worn out wheel bearing. However, this has been replaced and the same noise remains.

According to the mechanic who fitted the bearing, the brake cylinder is not leaking (on either side) and the existing shoes and drums are in serviceable condition. Pressing the brake pedal does not change the noise and the brakes are stopping the car as normal.

Is it possible that the nearside cylinder has partially seized without any sign of leakage or weeping behind the protective rubber boots?

Or could the noise be caused by something else such as a build up of rust on the drum?

Cheers,
Andy

 

[ZaphodB]

If you have access to a jack , you could lift that corner and test rotation yourself (with and without brakes applied)

If a mechanic who's got the wherewithall to replace a wheel bearing successfully, can't find out the source, I'd take it to another mechanic.......

Noise from a drum brake wheel is very simple, it's either the bearing or an element of the braking system...

(I was going to suggest it was possibly an ABS sensor kicking in on that corner , but it doesn't have ABS)

Is it a metallic grinding noise ?... if not could be the tyre touching the body perhaps, broken spring, but again I'd guess a mechanic capable of replacing a wheel bearing might notice something obvious like that.

 

[capers626]

If you have access to a jack , you could lift that corner and test rotation yourself (with and without brakes applied)

If a mechanic who's got the wherewithall to replace a wheel bearing successfully, can't find out the source, I'd take it to another mechanic.......

Noise from a drum brake wheel is very simple, it's either the bearing or an element of the braking system...

(I was going to suggest it was possibly an ABS sensor kicking in on that corner , but it doesn't have ABS)

Is it a metallic grinding noise ?... if not could be the tyre touching the body perhaps, broken spring, but again I'd guess a mechanic capable of replacing a wheel bearing might notice something obvious like that.

Hi ZaphodB,

Thanks for your input. Yes, on the face of it there are a limited number of brake related causes for the noise though it is intermittent. If, for example, it is down to a build up of rust you'd of thought the mechanic would have erred on the side of prepping the drum before reassembly...

I wouldn't say it's a metallic grinding noise though I could be wrong - it just sounds like something is stuck in the wrong position. According to what he said, everything is moving freely in terms of the action of the cylinder in tandem with the springs and shoes, which have little wear. He's going to take another look next week. Till then, I'm not going to risk driving the car.

Cheers,
Andy

 

[bugsymike]

It can be any number of things, the dust shield catching the brake drum,a brake shoe return spring rubbing, the hand brake balance bar between the shoes catching the hub, it could even be a bit of gravel caught in a front brake disc back plate as noises quite often are not where you may think they are coming from or a front brake pad worn down unevenly just touching metal to metal.
If you were to go for a drive , when noise occurs try very lightly touching the foot brake to see if it affects the noise, the same thing with the handbrake, not enough to slow vehicle, just enough to affect the brake mechanism.
The other thing you could try is seeing if going around a left or right hand bend affects it.
Many years ago I had a top of the range Peugeot 604 saloon with an occasional annoying rattle, just before selling it I found a spare caliper retaining clip lodged in the rear suspension from when a previous owner had work done.

 

[capers626]

It can be any number of things, the dust shield catching the brake drum,a brake shoe return spring rubbing, the hand brake balance bar between the shoes catching the hub, it could even be a bit of gravel caught in a front brake disc back plate as noises quite often are not where you may think they are coming from or a front brake pad worn down unevenly just touching metal to metal.
If you were to go for a drive , when noise occurs try very lightly touching the foot brake to see if it affects the noise, the same thing with the handbrake, not enough to slow vehicle, just enough to affect the brake mechanism.
The other thing you could try is seeing if going around a left or right hand bend affects it.
Many years ago I had a top of the range Peugeot 604 saloon with an occasional annoying rattle, just before selling it I found a spare caliper retaining clip lodged in the rear suspension from when a previous owner had work done.

Hi Bugsymike,

All useful suggestions though as I mentioned in my original post pressing the brake pedal does not change the grinding noise. I agree it is difficult to tell exactly where the noise is located but do think it is coming from the rear. Further investigation needed, ideally the mechanic will hear it from a test drive.

Cheers,
Andy

 

[bugsymike]

Hi Bugsymike,

All useful suggestions though as I mentioned in my original post pressing the brake pedal does not change the grinding noise. I agree it is difficult to tell exactly where the noise is located but do think it is coming from the rear. Further investigation needed, ideally the mechanic will hear it from a test drive.

Cheers,
Andy

Yes I did read that, but none the less sometimes those suggestions can make a change in the symptoms and help diagnosis.
Noises can be hard to locate, I always listened to what my customers said as they may not know the technical side, but as they drive the vehicle all the time, they have more knowledge in when it happens, sometimes a mechanic on his own may not even pick up the sound until the owner sat with him suddenly says "there it is".
Even recently on an old Skoda 4x4 of mine I heard a noise and it happened coincidentally as I pulled on the hand brake it failed, I put it down to a broken cable rubbing something, in the end when jacked up there were two faults, a rear self adjusting handbrake caliper accounting for the sudden extra handbrake travel and a propshaft rubber donut reinforcing band that had broken away from it's metalastic bush and touched the car chassis as you slowed down giving the rubbing noise, both oddly happening at that same time.

 

[capers626]

Yes I did read that, but none the less sometimes those suggestions can make a change in the symptoms and help diagnosis.
Noises can be hard to locate, I always listened to what my customers said as they may not know the technical side, but as they drive the vehicle all the time, they have more knowledge in when it happens, sometimes a mechanic on his own may not even pick up the sound until the owner sat with him suddenly says "there it is".
Even recently on an old Skoda 4x4 of mine I heard a noise and it happened coincidentally as I pulled on the hand brake it failed, I put it down to a broken cable rubbing something, in the end when jacked up there were two faults, a rear self adjusting handbrake caliper accounting for the sudden extra handbrake travel and a propshaft rubber donut reinforcing band that had broken away from it's metalastic bush and touched the car chassis as you slowed down giving the rubbing noise, both oddly happening at that same time.

Yes, ideally the test drive will take place with the mechanic and me in the car as the last time the noise was present he couldn't hear anything from outside and then it stopped all by itself! As the grinding is intermittent but regular (in the sense that it keeps cropping up randomly), I don't think a stone is likely to be causing the issue but stranger things have happened...

 

[capers626]

Hi all,

Quick update - the grinding noise is still there and seemed to come on suddenly after driving about four miles without any issues. The sense I get is that the rear brake shoes on the passenger side are making friction contact with the drum without pressing the brake pedal or gently applying the handbrake (which has no effect in both cases). On completing the journey, the nearside outer wheel plastic cover is quite warm whereas the other side is cold.

 

[bugsymike]

Hi all,

Quick update - the grinding noise is still there and seemed to come on suddenly after driving about four miles without any issues. The sense I get is that the rear brake shoes on the passenger side are making friction contact with the drum without pressing the brake pedal or gently applying the handbrake (which has no effect in both cases). On completing the journey, the nearside outer wheel plastic cover is quite warm whereas the other side is cold.

Sounds like a closer inspection of N/S/R brake is required.
Are you sure the handbrake cable is releasing fully on that side, it is quite common for them to partial seize?

 

[capers626]

Gently moving the handbrake had no effect on the noise when the car was moving but I will double check to see if partially seized on the nearside.

Thanks

 

[bugsymike]

Gently moving the handbrake had no effect on the noise when the car was moving but I will double check to see if partially seized on the nearside.

Thanks

What I would do is remove the brake drum , make sure everything is working correctly and brake cylinder pistons free, so if you had two screwdrivers you could rock the shoes and pistons lightly, side to side ensuring they are free, I believe you mentioned flicking back the dust covers to check for impending fluid leaks, I used to do that on every service on customers vehicles.
Not common , but sometimes handbrake lever inside brake drum seizes at pivot point.
After with wheel off the ground and spinning freely, pull hand brake on firm , then release slowly and check brake drum still spinning freely.

 

[ZaphodB]

Gently moving the handbrake had no effect on the noise when the car was moving but I will double check to see if partially seized on the nearside.

Thanks

What if you try and apply it (gently) before the noise comes on?

 

[capers626]

I would expect there to be a slight friction noise which would be normal but nothing like the grinding effect when I think the shoes are stuck and making excessive contact with the drum.

 

[ZaphodB]

I would expect there to be a slight friction noise which would be normal but nothing like the grinding effect when I think the shoes are stuck and making excessive contact with the drum.

But applying the handbrake before the noise starts would have the exact same effect.
If you can't replicate it by applying handbrake (before it starts), then it's not the handbrake at fault imo.
I think it's something else.

Shoes and drums in good nick won't make a metallic sound , and your mechanic has already said they're in good servicable nick.

 

[capers626]

I'm not sure (it's a metallic sound), further investigation needed, no easy answers to these kinds of issues, much as I would like there to be.

 

[capers626]

Took my car in today and after removing the brake drum on the nearside, a loose retaining clip was found. As I had already anticipated it would be a good idea to change the springs, posts and clips as part of the process of removing the brake shoes before fitting a new wheel hub, it seems that my mechanic thought otherwise. Given the condition of the posts in particular, this was false economy (in my opinion).

The mechanic did take the opportunity to blast off a ridge of rust on the inside of the back plate all the way round and then fit most of the accessory kit (on both wheels) at no extra cost. All seems to be okay now . Thanks to everyone who contributed to this thread.

 

[ZaphodB]

Original "mechanic" needs sacking