| Author |  Topic  |
PDickens
V4 Mad
United Kingdom
519 Posts |  Posted - 08 Sep 2012 : 15:25:17  
| My car has been out of action for a month or two because of holiday, work, and a horrid grinding noise I get on braking. It seems to come from the front nearside. Today I had a look - I thought it might be the brake piston sticking but it seems OK and the pads could be moved on that side. Everything seemed OK on visual inspection. It was OK when I reversed it out of the garage, and for a few hundred metres until I braked and the noise returned. I noticed some fluctuation in pedal pressure and they felt a bit spongy afterwards even though I had bled them beforehand. The noise continues even when the brakes are not being applied then dies away - it also seems to come on most when turning while braking. I haven't noticed any sign of the brake sticking on, which would happen if the piston was sticking once out? Also it had new pads, rotors and backplates last year and I've done less than 1000 miles since then - both discs and rotors looked fine on inspection.
Could I be barking up the wrong tree here - might it be a transmission issue - cv joint or driveshaft problem? Wheel bearing? Thoughts very welcome - I hope to have it sorted ready for John Wyatt's run on the 30th Sept, but a transmission job is beyond my skills. |
Edited by - PDickens on 08 Sep 2012 15:47:21 |
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ianh
V4 Fanatic
United Kingdom
250 Posts | Posted - 08 Sep 2012 : 16:26:25
| | I had a similar situation, fast drive to the airport in the rain. Parked up for two weeks and driving out of the car park after my holiday an awful screech as I stopped to pay. Had a look at the front discs and they were both rusty. I drove home with lots of noise and juddering on braking. It doesn't stay out in the rain anymore! |  |
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transit80
V4 Mad
United Kingdom
775 Posts | Posted - 08 Sep 2012 : 18:18:17
| Hi Paul, have you looked at the pads??,one may have worn right down to the metal.
Chris | |
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PDickens
V4 Mad
United Kingdom
519 Posts | Posted - 08 Sep 2012 : 19:17:15
| Cheers guys - Ian I never take it out in the rain as my feet get wet!
Chris - they looked OK but will have another peep - they've less than 1000 miles on them! Funny they were squealing before the noise started.....hmmmm | |
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john-saab
Administrator
United Kingdom
2682 Posts | Posted - 08 Sep 2012 : 20:09:20
| I have had this several times..normally a stone caught in the pads..I usually reverse hard then brake..that throws the stone out!
'72 95 (The Flying Banana),'72 96 (Bridget),'74 95 (Veronica) | |
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Andyinthegarage
V4 Fanatic
United Kingdom
361 Posts | Posted - 09 Sep 2012 : 00:59:58
| quote:
Originally posted by PDickens
Could I be barking up the wrong tree here - might it be a transmission issue - cv joint or driveshaft problem? Wheel bearing? Thoughts very welcome - I hope to have it sorted ready for John Wyatt's run on the 30th Sept, but a transmission job is beyond my skills.
Brakes are tempremental, they may appear to be working within bounds but are fickle! My suggestion would be to go for the easy test first. Strip, clean and rebuild the brakes one corner at a time.
I doubt it is transmission train, sounds more like a slightly dragging brake. Does it get hot?
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Edited by - Andyinthegarage on 09 Sep 2012 08:04:51 | |
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PDickens
V4 Mad
United Kingdom
519 Posts | Posted - 09 Sep 2012 : 11:26:59
| | Spoke to my engineer neighbour today and he thinks its likely the brakes too. So plan to strip down the nearside one first (which is where the noise is coming from. I've got a new set of calliper pistons too so will fit them in case that's what the source is. | |
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PDickens
V4 Mad
United Kingdom
519 Posts | Posted - 09 Sep 2012 : 12:51:29
| Problem solved but not resolved!
Took off the wheel and found that the outside edge brake pad had dropped onto the disc and the bottom of it had been rubbing - hence the grinding metallic sound. Trying to refit the pad and it keeps falling off the "shoulders" - could be a duff pad or wear on the calliper. Comparing the shoulder on the outer pad and the inner one (which fits snug) they look the same, so at the moment think its the calliper. As usual always the more expensive thing to replace!! :( | |
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john-saab
Administrator
United Kingdom
2682 Posts | Posted - 09 Sep 2012 : 17:06:43
| See this thread..
http://www.saab-v4.co.uk/speedball/topic.asp?topic_id=3214
I went though all 6 of my spare calipers and all were either the same or worse so i'm going to spend a bit of time overhauling them all..basically shot blasting then welding the sholders.
'72 95 (The Flying Banana),'72 96 (Bridget),'74 95 (Veronica) | |
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melle
V4 Guru
United Kingdom
4145 Posts | Posted - 09 Sep 2012 : 22:03:59
| Bought a set of freshly refurb'd callipers once, corners were completely shot despite their shiny golden coating. Supplier wouldn't give me my money back because they had been installed... I do all overhauls myself since, same procedure as woody's/john-saab's.
1970 96V4 "The Devil's Own V4"
1977 95V4 van conversion project
1988 900i 8V | |
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john-saab
Administrator
United Kingdom
2682 Posts | Posted - 10 Sep 2012 : 08:32:48
| I have brand new caliper seals arriving late this week if you plan to referb your calipers when they are off.
'72 95 (The Flying Banana),'72 96 (Bridget),'74 95 (Veronica) | |
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Woody
V4 Guru
United Kingdom
2878 Posts | Posted - 11 Sep 2012 : 20:58:08
| If you haven't used the vehicle a while the discs rust up, therefore they are noisey for a while until the pads have polished them up again. Were the brake flexis in good condition? Outwardly they can look in fair condition but could have swelled on the inside causing poor operation. Good to get someone to stand on the brakes while you observe what the caliper is doing. Were the pistons clean? If the vehicle has been stood it is useful to remove the pads and press the pedal to push the pistons out a bit to check there aren't any rust spots on the surface which would restrict piston movement/retraction.
I have had experience where the caliper has made a grinding/clunking sound due to wear/spring weakness at the bottom pivot and the upper spring loaded slider/retainer having seized so the two halves chatter. | |
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PDickens
V4 Mad
United Kingdom
519 Posts | Posted - 12 Sep 2012 : 16:33:21
| Thanks for your thoughts everyone.
The issue is the pad is dropping through the caliper - the shoulders isn't catching in the slot as intended. Anyway I've bought a pair of refurbed calipers on exchange and new pads and will put them on this weekend. Hopefully problem resolved....... | |
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Woody
V4 Guru
United Kingdom
2878 Posts | Posted - 12 Sep 2012 : 18:59:34
| | AAH, I missed your post of the 9th. Hope your replacement calipers solve the problem. | |
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PDickens
V4 Mad
United Kingdom
519 Posts | Posted - 12 Sep 2012 : 19:34:26
| | No problem Woody - also have checked the fit between pad and new caliper (only one arrived so far) and it sits solid so don't think I will need to weld up the shoulders as suggested. | |
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PDickens
V4 Mad
United Kingdom
519 Posts | Posted - 22 Sep 2012 : 17:50:05
| | New calipers fitted and took it a run to bed the brakes in. All went well until I got back and found a nail through one of my tyres - and the spare has a slow puncture too! Sods law prevails!! | |
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| Topic | |
Horrid noise on braking - help!
