Topic

By: Chargerate
Posts: 24
Joined: 03/11/08

backwards-forwards brake clunk

Posted: Jan 28 2010 Tags: brakes, clunk, nc Views: 94

Just recently my 3k mile NC has developed a 'drive backwards then brake (even gently) 'clunk' - then drive forward, brake,clunk". Seems to be coming from nearside rear.

Never had this before on a rear disc- braked car so it doesn't feel right. Almost sounds the the pads settling into a new position. Could also be the caliper too I guess.

My question is has anyone had this - is it common? I plan to get the wheel off and check the obvious bolts but would be good to have a heads up.

Replies

RE: backwards-forwards brake clunk

I think you've answered your own question, all i can suggest is do it sooner rather than later!

Good luck Dave.

CHATSWORTH 19th Sept 2010 be there!

Posted: Jan 28 2010 By: Posts: 823
RE: backwards-forwards brake clunk

Hi there

It could be a loose caliper bolt, a pad carrier not torqued up to the hub correctly or a sticking piston on the caliper, I would be tempted to have to caliper checked to see if the caliper piston is not binding.

You can have a twisted seal in the seal groove inside the caliper!!! Common fault with auto piston insertion on auto assembly lines, they will still seal off under test but will cause the piston to bind with the twisted seal and when you apply the brakes the piston will stick or bind then move under more pressure resulting in a clunking sound.

It might just be a pad shim off one of the rear pads which is simple to fix...

Regards

Jeff

Posted: Jan 28 2010 By: jeff5 Posts: 679
RE: backwards-forwards brake clunk

I have this also - but I think it's from the front brakes.

I asked them about it at the last service, but they just said it was the pads moving in the shims, and said they'd just grease it up. I think it was gone after the service, but it's back again already. I don't see how grease would fix a clunk though.

Hope it isn't anything untoward, else I'll be rather annoyed that they lied. I don't even have to move backwards for it to clunk IIRC.

Posted: Jan 29 2010 By: Mazrus Posts: 1345
RE: backwards-forwards brake clunk

Hi

Thats strange when you say you have the same clunk even when not moving!!!

Have you checked to see if any of the carrier shims are missing or even broken? there could also be a pad shime missing from one of the pads, have someone pump the brakes to see if you can hear the clunking or even take the wheels off for a closer inspection.

If you are still not sure take your car to someone else just to make sure that all is ok.

Regards

Jeff

Posted: Jan 29 2010 By: jeff5 Posts: 679
RE: backwards-forwards brake clunk

Take the wheel off and block the car up (not with the jack), with it being rear wheel drive you can then get somebody to sit in the 5 and carefully and slowly run in 1st gear then in reverse while GENTLY applying the brakes. Then refit the wheel bolts apply the hand brake use a crow bar or something similar turn the hub assembly back and forward, this will show up any loose pads or bolts.

Hope this helps, Dave.

CHATSWORTH 19th Sept 2010 be there!

Posted: Jan 31 2010 By: Posts: 823
RE: backwards-forwards brake clunk

29/01/2010 09:25:57, jeff5 said:
"
"

Sorry Jeff, I think I've misled you. I only get the clunk when moving, but I don't have to move backwards to get the clunk. I.E. I'll get it many times on the way home, moving only forwards, never backwards.

A while back I heard a loud ping from the front driver's side area (where the clunk seems to come from) and soon after I noticed the clunk. Despite telling my dealer this, they still say the shims just need greasing up. Again, I don't see how grease will stop a clunk. However, the clunk seemed to disappear for a while after the last service - or I just didn't notice it for a while, perhaps.

Hi

Thats strange when you say you have the same clunk even when not moving!!!

Have you checked to see if any of the carrier shims are missing or even broken? there could also be a pad shime missing from one of the pads, have someone pump the brakes to see if you can hear the clunking or even take the wheels off for a closer inspection.

If you are still not sure take your car to someone else just to make sure that all is ok.

Regards

Jeff

Posted: Feb 01 2010 By: Mazrus Posts: 1345
RE: backwards-forwards brake clunk

29/01/2010 09:04:13, Mazrus said:
"I have this also - but I think it's from the front brakes.
I asked them about it at the last service, but they just said it was the pads moving in the shims, and said they'd just grease it up. I think it was gone after the service, but it's back again already. I don't see how grease would fix a clunk though.

Hope it isn't anything untoward, else I'll be rather annoyed that they lied. I don't even have to move backwards for it to clunk IIRC.
"

I thought I read somewhere this was the ABS self-test on starting up, not that I have heard the clunk on mine except when I come to use it the day after washing it, and that is usually from the rear.

Mazda5 & MX5 LE

1969 MGB GT & 1968 MG1300

Posted: Feb 01 2010 By: Martin Posts: 261
RE: backwards-forwards brake clunk

01/02/2010 12:52:02, Mazrus said:
"
29/01/2010 09:25:57, jeff5 said:
"

"Thats ok Mazrus

I would check to see if the carrier shims on the leadind edge of the pad carrier are still there or is one of them broken!!!

If you say you heard a pinging sound from that area also check to see if both the pad springs are there especially the outboard pad the inner pad will be up against the piston and under more load when braking.

There must be some sort of movement of the pads somewhere!!!

Regards

Jeff

Sorry Jeff, I think I've misled you. I only get the clunk when moving, but I don't have to move backwards to get the clunk. I.E. I'll get it many times on the way home, moving only forwards, never backwards.

A while back I heard a loud ping from the front driver's side area (where the clunk seems to come from) and soon after I noticed the clunk. Despite telling my dealer this, they still say the shims just need greasing up. Again, I don't see how grease will stop a clunk. However, the clunk seemed to disappear for a while after the last service - or I just didn't notice it for a while, perhaps.

Hi

Thats strange when you say you have the same clunk even when not moving!!!

Have you checked to see if any of the carrier shims are missing or even broken? there could also be a pad shime missing from one of the pads, have someone pump the brakes to see if you can hear the clunking or even take the wheels off for a closer inspection.

If you are still not sure take your car to someone else just to make sure that all is ok.

Regards

Jeff
"

Posted: Feb 01 2010 By: jeff5 Posts: 679
RE: backwards-forwards brake clunk

Thanks Jeff, but what do the pad springs look like? Surely one shouldn't just ping off under a quick dab of the brakes? And I'd have hoped that the Mazda mechanics would've noticed that!

I assume the wheel needs to be removed to see this stuff?

Posted: Feb 02 2010 By: Mazrus Posts: 1345
RE: backwards-forwards brake clunk

OK, here's what I found.

Lot's of stuff on web saying that this is a common characteristic (on all cars) even a service tip from Nissan advising dealers to fit modified shims if the customer complains of the same.

Checked the 'moving caliper' pin bolts and fixed caliper to hub bolts and both sets secure.

managed to move the pads 1-2mm back and forth by sticking a screwdriver in leading and trailing edges of pads - no surpises there that this would cause a clunk when there's the force of the car behind it.

Listening *very* carefully, you can actually hear both sides clunking, albeit at slightly different times.

Not concerned at all...

Posted: Feb 02 2010 By: Chargerate Posts: 24