 You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more
A distinct clunk from the driver's side front wheel area when applying the brakes when reversing. It won't do it again until the car has been driven forwards.
It is almost like the pads move slightly in the caliper, but the retention springs at each end seem to both still be there.
2005 Berlingo BTW...
Any pointers much appreciated.
Are the pads very worn?
I don't think so. It had MOT today, which should include a visual check of depth of friction material. The front spring was cracked, so replaced, and I thought this would explain the clunk, but it is still there...
You can be down to 1.5mm of pad material before you get warned on the MOT, from about 12 on some pads, meaning your pistons are a long way out and your heat dissipation is really poor - MOT isn't a very good service check! Also you could have pad movement due to worn pads or mount areas. Or you could have worn caliper slider pins. Or you could have worn suspension bushes (I'm not sure of the configuration of the berlingo front end but I'm guessing it's mac struts so either the inboard mounts or maybe, but unlikely, the ARB if it's a strange configuration.
If it only occurs when you lightly breathe on the brakes it's probably the pads shifting in the caliper. check retaining parts, if OK ignore it.
Was it clunking before they changed the spring? If not take it back
Could also be a drive shaft.
Also, in light of the spring post which I missed, top mount bolts/nuts tight? Arm bolts tight? Driveshaft properly torqued? Any play in the wheel? Did they remove the caliper during the change (shouldn't need to but may have to prevent hose being pulled so it might not have been re-fitted properly?
In light of replaced spring the possibilities are fairly large. I'd personally return it and ask for it to be fixed, AFTER checkign to see if they forgot something dangerous - which isn't uncommon.
Thanks. I'll have a closer look tomorrow. Given that a new spring was fitted today I guess the garage would have spotted any wear in the suspension system.
I'll check the pads. Min thickness is 2.0mm, I'll measure the discs too.
I assume the clunk is unlikely to be driveshaft/wheel bearing related.
EDIT: The clunk was there before the visit to the garage today. I didn't know about the broken spring. That was picked up during the MOT and sorted there and then. There is no new issue. When the mechanic told me about the spring, I thought "oh, that explains the clunk", but the clunk is still there.
could also be broken bits of suspension. get that corner of the car jacked up & see if you can move the wheel more than you'd expect to be able to in any direction other than round
EDIT: The clunk was there before the visit to the garage today. I didn't know about the broken spring. That was picked up during the MOT and sorted there and then. There is no new issue. When the mechanic told me about the spring, I thought "oh, that explains the clunk", but the clunk is still there.
Most likely to be the brake pads shifting in the caliper then. Pads have to have clearance to move or they'd bind. Naturally the springs, clips and design hold them in the right position for normal (forward) use so they shift when being used backwards. The older the pads, the more rust that has accumulated and worn off, the further out the pistons are the more likely the clunk is noticable. Check it over for peace of mind but it's not unusual.
Cheers. Copper grease on the back of the pads a good idea, or not?
Sounds like a driveshaft to me, had that on a Ford, was told to ignore it until it started knocking when driving.
Does it do the same if you're on full lock?
Sounds like a driveshaft to me, had that on a Ford, was told to ignore it until it started knocking when driving.Does it do the same if you're on full lock?
That woudl be an outer CV joint, it shouldn't t knock on touching the brakes in reverse. The reason CV's knock is due to wear (often due to a split boot allowing grit in) in one location of their operation, when turned they ride through this wear at an angle and clunk. Shouldn't really be a driveshaft issue at all as all of the torque from the braking action is being taken by the bearing carrier, there should be no torque down the driveshaft and generally CVs don't clunk with no torque through them unless they're *properly* knackered, or an inner CV, and even then it's repeated 3 times per rotation.
Cheers. Copper grease on the back of the pads a good idea, or not?
Persnally I rarely bother unless I have squeel issues, and even then it's not really a cure. You need to see what's worn and replace it (if anything, as I say - it's fairly normal)
Just a side point, if it gets notably louder, re-assess.
Always just one clunk, and just as the brakes bite.