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Hi,
I'm having the exact same symptom as you described last week (?) -
vibration when coming to a near stop, but at no other speed. Feels like
the road is grated.
Have you found out what's causing it? I couldn't send you mail, hence
this post. I've been having a lot of work done on several cars, so trying to
prioritize the service/repair based on severity.
This happened fairly recently, so I know it's not due to rear brake job I did 2k miles ago.
Thanks!
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Thanks everybody - so almost everything points to the rear brakes. Use OEM rotors and pads. If the pads are SB/TNN (old OEM parts), you need metal cut away shim, if the pads are new OEM parts, no shim is necessary since that feature is already incorporated.
Just so I understand it clearly, the shim/new pad eliminates vibe due to a change in contact angle with the rotor surface, it sounds like? I can see how the pad can 'skip' along the rotor surface and create vibes, if sitting at a wrong angle.
It sounds like either my indy shop used an old OEM part, or a non-OEM part, even though I was told they use OEM parts. Neither makes me feel good. The rear brakes were done ~ 2 mo ago. Perhaps the pads just need adjustment. At least I'll sound like what I'm talking about when talking to them, which is as good as saving money.
One final(?) question is whether I need to get this done right away or not. Other than the possibility that this 'vibe' will induce more rattle inside the car by knocking things around and loosening them, how bad do you think it is to live with it for another couple of months? Others had to live with the problem for several months with no dire consequences, so I'm guessing it's ok.
I've been getting too many things done to the car(s) lately, including tinting, so need a break from spending money if possible.
Chances are, I'll make a call later today to a shop anyway, but...
Oh, another question - is this problem specific to FWD Volvos? I haven't had this in my 940.
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"if the pads are new OEM parts, no shim is necessary since that feature is already incorporated."
Be careful with the word OEM. I'm not positive but it is my understanding that OEM is not the same as Volvo. You can search the archives on this site for that topic. To solve my rear brake problem I used new Volvo pads AND the Volvo cut-away shim. I don't think new Volvo pads has a built in CUTAWAY shim.
"how bad do you think it is to live with it for another couple of months? Others had to live with the problem for several months with no dire consequences, so I'm guessing it's ok."
The only reason I lived with it is because my wife drives the car :) She complained every few days and I "quickly" solved the problem - a few months later! I drove it once in the mountains and thought I was going to die. The horrible noise and vibration was constant with every downhill braking.
Bottom line in $ was about $140 for two rotors, $35 for pads, $20 for shims and silicon grease. I did the labor. After all the messing around I did to discover the true fix, I would have willingly paid the dealer the $500 or so they want for rear brakers and rotors!
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posted by
someone claiming to be Tim
on
Wed Aug 14 23:59 CST 2002 [ RELATED]
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OEM part means original equipment part like what the car came with from the factory, what you'll get if you buy a new part from your Volvo dealer.
The newest type rear pads are not "cutaway", they have a rubber type backing which is attached to the backside of each pad, not removeable.
Although I've seen the half-shims on a few cars (and seen the old SB on this), our dealer has never sold or installed them nor have we seen any problems w/o their use. The older OEM Volvo pads originally came with 2 shims per pad and one would install them with silicone paste on each shim w/o problems at our dealership. Volvo sells and recommends a silicone brake paste that's applied to the backside of new pads which has been around since the 80's (700s) and we use it with every brake job. Our brake jobs do not return to us with any noise or vibration problems nor have they ever.
Rear calipers, pads and rotors on 850s, X70s are almost identicle to what was used in the 80s on 700s and although they have different PNs, 700 and 850 rear pads can even be interchanged (although I'm not advising this here).
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Another dumb follow-up question - can one have this vibe in brakes in the front, or is this rear brake only symptom?
I talked to my indy shop, and they swear by using OEM (Volvo) brake parts, rotors & pads. They only did the rear, and wondering if the vibe is coming from the front. The front got done before I purchased the car, so I have no idea what parts were used (even though the work was at a dealer).
Tim - what state is your dealer in? Recommend any in MA?
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posted by
someone claiming to be Tim
on
Tue Aug 13 13:44 CST 2002 [ RELATED]
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The half shims previously described are discussed in an old SB or TNN (couple years now) and the parts have been since superceeded to a newer type brake pad that has no additional shim required. The new pads have a rubber type backing instead.
If you have both rotors and pads replaced with OEM, you won't need the old type pads with the half-shims anymore as this info is now obsolete. Any dealer should now stock and sell the new type pads.
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posted by
someone claiming to be johnh
on
Tue Aug 13 09:58 CST 2002 [ RELATED]
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Read the following response to FFF88's post. Murray3331 knows what he's talking about! Fixed mine after living with it for over six months. Make sure you ask for the cutout metal shims that are part of a service campaign. They're designed to apply unequal pressure to the pads during braking. The embossed arrow on the shims are supposed to point up. If there's any wear on the pads you might need to replace them also.
"by Murray3331 on Tue Aug 13 00:09 UTC 2002
Author Info: [PROFILE] [EVERY POST] [THREADS]
I think I know what is causing your problem, I have had it on my 850 as well. Volvo makes a set of shims for the rear brakes. On some models you must install this shim to adjust the angle of the pad. I believe there are two types - a teflon and ?? Anyway, I think this will correct your problem. It sounds identical to what I had... and BTW the dealer did the rear brakes, rotors etc, and didn't re and re the original shims I had... great service eh?
Shims are around $15 and 1/2 hour labour"
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Thanks for the post, johnh.
I figured I should take FFF88's handle off the subject. :)
You say the metal shims are a part of service campaign - meaning the work is free at a dealer?? I had my rear brakes done at an indy shop, with OEM rotors, pads, etc., ~2 mo ago. Any idea how indy shop handles service campaigns?
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posted by
someone claiming to be johnh
on
Tue Aug 13 13:27 CST 2002 [ RELATED]
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They weren't free, at least in my case. (Cost about $10.00 for a set of four.) You use one on each rear brake pad. The Volvo parts guy told me they were a service campaign kit to eliminate rear brake pad vibration. Basically, they're metal shims with a cutout on one half. Half the brake piston contacts the shim while the other half directly contacts the pad backing. For about six months, my '94 850T had an intermittant but severe vibration that shook the whole car when braking from about 10 mph until stopped. I traced it to the left rear wheel by repeatedly braking from slow speed while an outside observer took note of where the noise was coming from. I changed the rotor once and the pads twice to no avail. Tried standard shims then no shims. The vibration usually went away for a day or so then came back as before. I was getting ready to order a new caliper, thinking it might be dragging and overheating. Not sure where I heard about the shims, but probably read it somewhere. Went to the dealer parts counter and said I'd heard about a shim that reduced brake vibration. Parts guy knew what i wanted and an hour later they were installed. (Just on the left side, still haven't got around to putting them on the right.) I haven't had even a hint of vibration since installing the shims.
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I have exact same symtom. Try to double check your brake pads, if install correctly, and if your brake pads bend a little bit outward over time. That's what happen to my car. I'm using X-drilled rotors and KVR pads though.
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If you give me more details I may have had the exact problem that took me months to fix. If it is the same I can save you a lot of time and hassle. Is it when braking to a stop, the brakes are hot, and the entire car vibrates horribly?
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Torque - it happens only when I'm coming to a stop, just before a full stop at < 5mph, not at any other speed, doesn't matter how lightly I brake.
Not sure whether this happens only when brakes are hot (wife's car, have it for the day), but first noticed in the middle of the commute, so I'm guessing that is the case.
It's not the wobbly shake you get when the rotors are warped. Higher frequency, and very noticeable. The best way I can describe is, I thought I was braking on top of grated pavement, you know that kind that's used to indicate lane changes and shoulders. When it happened more than once, I thought it was funny, since I never noticed grated road during the commute before.
So, what was the cause and how did you fix it? Engine mount? Exhaust?
No recent work done over 2 mo, btw.
TIA.
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Sounds exactly like my problem. First I replaced the front pads and rotors because they were almost due. Didn't work. I had nearly new rotors and pads (aftermarket)on the rear. Thought I had it licked, but NO. I finally gave in and went to the dealer. Got the service guy to ride with me. The head service guy that really knew Volvos. It took awhile to make it happen with him in the car but finally it did it, just like riding over a rippled road, heavy vibration. He immediately said it is the rear and I should go with OEM pads. I then replaced the rear pads with OEM, even though they were still at 90% and only a couple of months old. Didn't want to replace the rotors since they were so new, & no warpage. I sanded the rotors. The OEM pads seemed to do it for awhile but then it raised its ugly head again. So I replace with rotors with OEM and am a happy camper again. This process took 4 months!
Bottom line: put on Volvo pads, Volvo rotor, and Volvo cut-away type rear shims. The service guy said that is the only sure fix and I believe him.
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How long have you been vibe-free (when did you get oem brake parts installed)?
I had my rear brakes done ~2 mo ago at an indy shop, where they supposedly use all oem brake parts for brakes. Maybe they didn't know about the cutaway shim. Maybe they cut corners (hopefully not, 'cause if so, I'm changing to a different shop in a heartbeat).
Thanks, Torque.
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I have been vibration free for about 4 months. I am totally convinced the Volvo service manager was correct. I thought just doing the pads in the rear would work but he thinks that somehow the rotor, even though nearly new, gets to a state, perphaps due to heating, that the pads "skid" a little on it rather than bite. I have a 240 and a 850 and have been doing my own brakes for about 3 years. I don't consider myself an expert but I have learned a lot. I was buying PBR or Mintex pads and Brembo rotors to save a few dollars. But at least for the 850 I will stick with buying Volvo parts. Another point to consider: the book says to change the caliper bolts each time you change the rotor. However only Volvo rotors come with the caliper bolts. They are hard to find otherwise. So I now have new bolts once I installed the Volvo rotors.
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Thanks Torque - it wasn't to doubt your solution, but to compare the vibe-free duration on your car with mine. I'll have to ask my indy shop to see if they indeed used OEM parts as advertized, and whether they used pad with built-in shim or not.
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I have not had time to check the motor mount. I am not sure what it is yet. I do have the cutout shims on my fresh OEM pads. I am going to check the motor mounts and if they are not broken, take off all the pads and check them and reinstall. I feel it may be the mount though. And it does seem to start when the brakes are hot. Torque, what was your fix???????
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