1995 Volvo 850 Brake Vibration Noise

Tiny
DCJMED
  • MEMBER
  • 1995 VOLVO 850
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 14,000 MILES
Recently, the rear brakes make a noise that I can only describe as a vibration based humming. It started happening when I drove it during wet weather, but recently it has been happening more often. It also only happens when the brake pedal is fully released, as soon as I depress the pedal the noise stops. I recently had the oil changed and the brakes checked by my long term mechanic and he said that the brakes themselves were in fine condition. Any ideas?
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Saturday, September 20th, 2008 AT 1:12 PM

9 Replies

Tiny
MERLIN2021
  • EXPERT
There is a tech bulliten on your brakes, they need shims, rad about it:
BRAKE SHIMS -MINIMIZE RESONANCE VIBRATIONS REAR AXLE -1995 Volvo.
Page 1 of 3
BRAKE SHIMS -MINIMIZE RESONANCE VIBRATIONS REAR AXLE
TECHNICAL SERVICE BULLETIN
Reference Number(s): GROUP 51, NO. 803, Date of Issue: August, 1996 Related Ref Number(s): GROUP 51, NO. 803
ARTICLE BEGINNING
NEW SHIMS TO MINIMIZE RESONANCE VIBRATIONS, REAR
Model(s): 1993-97 Volvo 850
Section: 5 - Brakes
Group: 51
Bulletin No: 803
Date: August, 1996
REFERENCE
TP 5001201, Section 5, Brakes (incl. ABS and TRACS); 850 1992-On. TP 5002202, Section 5 (50, 52, 55, 59) Brakes (incl. ABS and TRACS); 850 1996-On.
SERVICE INFORMATION
If a customer complains of resonant vibrations from the rear of the car when braking at low speed (frequently when the brake discs are hot after repeated braking), the problem can be fixed by replacing the shims. A kit with a new type of shim has been produced for the rear brake calipers. The kit has P/N 272272-6 (kit contains 4 shims).
NOTE: Resonant vibrations are experienced usually when the car has new rear brake discs/pads.
The service manual referred to in this service bulletin is the Service Manual Section 5:
Brakes (incl. ABS and TRACS) 850 1992-On TP 5001201 or
Brakes (incl. ABS and TRACS) 850 1996-On TP 5002202.
PROCEDURE
1. Before replacing the shims the brake pads must be removed. See Fig. 1. 2. Remove rear wheels.

9/20/2008
BRAKE SHIMS -MINIMIZE RESONANCE VIBRATIONS REAR AXLE -1995 Volvo.
Page 2 of 3
REMOVING BRAKE PADS
1. Push out split pins with a 3 mm (0.12") punch. See Fig. 2. 2. Remove retaining spring. 3. Remove brake pads and shims. Use puller 999 2917-6 if brake pads will not come out easily.
CLEANING AND CHECKING
1. Clean brake pad contact surfaces in brake caliper. 2. Check piston boot. 3. If piston boot looks worn, replace it as a precautionary measure. 4. If the piston boot is damaged, recondition the brake caliper according to Service Manual section KD, (or PPP) "Disc Brake Caliper Rear, Recondition". 5. Press pistons back with a adjustable pliers (water pump pliers) or press tool 999 2809-5. See Fig. 3. Take care to avoid damaging piston boot. 6. Check that piston boot is in the proper position.
INSTALLING THE SHIMS
1. Grease the shims on both sides with a thin layer of silicon grease, P/N 11613254. 2. The new type of shims has a cut-out. The shims must be installed with the cut-out facing down in the disc brake caliper. See Fig. 4.
INSTALLING BRAKE PADS
1. Install brake pads. 2. Install one split pin and retaining spring first, then the other split pin. See Fig. 5.
WARRANTY INFORMATION
Claims may be submitted under the New Car Limited Warranty when there is a documented customer complaint for brake resonance using claim type: 01.
OPERATION NO: 51913-2 - Shims rear brakes installation.
TIME ALLOWANCE: 0.5 hr.
Fig. 1: Brake Pad - Remove
Fig. 2: 3 mm (0.12") Punch - Push Out Split Pins
Fig. 3: Water Pump Pliers & Press Tool P/N 999 2809-5
Fig. 4: Shims - Installed W/Cut-Out Facing Down In Brake Caliper
Fig. 5: Brake Pads, Install Split Pin & Retaining Sprint, Then Second

9/20/2008
BRAKE SHIMS -MINIMIZE RESONANCE VIBRATIONS REAR AXLE -1995 Volvo.
Page 3 of 3

9/20/2008
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Saturday, September 20th, 2008 AT 4:20 PM
Tiny
DCJMED
  • MEMBER
This information was very helpful, I just have one more question. This noise occurs when the brakes are NOT being used. As soon as I depress the brake pedal the noise stops. I just wanted to make this clear because from your message, it seems that the resonance vibration that is being addressed is occuring when the brakes ARE being used. I don't know if this is relevant but thought I would double check.
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Sunday, September 21st, 2008 AT 7:14 AM
Tiny
MERLIN2021
  • EXPERT
My experience with Volvo brakes lead me to this conclusion. Reverse usually is worse than drive, but not always. Get the shims, you will notice the difference! Part number is in my first reply.
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Sunday, September 21st, 2008 AT 7:24 AM
Tiny
DCJMED
  • MEMBER
Is there any danger, or chance of causing other damage, by driving the car before I install the shims?
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Sunday, September 21st, 2008 AT 8:48 AM
Tiny
MERLIN2021
  • EXPERT
No, it's not a saftey problem, just annoyance!
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Sunday, September 21st, 2008 AT 9:06 AM
Tiny
DCJMED
  • MEMBER
Thank you so much. Your information was excellent, prompt and very thorough. Well worth the donation.
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Sunday, September 21st, 2008 AT 9:11 AM
Tiny
MERLIN2021
  • EXPERT
Your kindly welcome! And thaks for the donation.
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Sunday, September 21st, 2008 AT 1:19 PM
Tiny
SULLY
  • MEMBER
I just wanted to say thanks for the info. I have a 1995 Volvo 850 and was experiencing the same vibration as the original poster. Mine started during slow right turns while applying the brakes, and later became more frequent especially during stop and go traffic.

I came across this thread last week and followed the instructions of the Tech Bulletin. The shims cost me about $13 from the Volvo dealer and about 30 minutes per side. I noticed my pins (especially on the rear left) had a lot of corrosion, I cleaned them well and applied plenty of silicone grease. No more vibration!

Thanks again for supplying this information.
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Tuesday, November 4th, 2008 AT 6:49 PM
Tiny
MERLIN2021
  • EXPERT
Your welcome fellas.
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Thursday, November 6th, 2008 AT 1:04 PM

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