1995 Volvo 850 Brake Vibration Noise

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?

9 Replies

MERLIN2021

MECHANIC
17,250 POSTS

There is a tech bulliten on your brakes, they need shims, rad about it:
BRAKE SHIMS -MINIMIZE RESONANCE VIBRATIONS REAR AXLE -1995 Volvo.
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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.
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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.
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9/20/2008