Hello all,

My son got a 97 850 wgn last fall. It had new brakes (which are now squeaking). I had the opportunity to drive it to work today and noticed that when I apply a light brake pedal the car feels like it wants to travel laterally left. I've had brakes that pulled before and this is different. It seems like something in the suspension is shifting. There is no clunk or anything, it just tries to shift left.

Has anyone else felt this problem or have an idea where to start looking? I can't let him drive it until this is figured out.

Thanks in advance!

Tim Benner
Dayton Ohio

 

Hi Tim,

Greetings from Yokohama, Japan.

I can think of the following from your descriptions + my sleepy head (currently it's 1:15a.m in Japan):

1. Uneven braking due to uneven component wear (brake pads/rotors). Did you replace the components with OEM parts?
2. Wheel alignment out of spec.
3. Uneven tyre pressure or lesser-grade tyres.
4. Loose suspension component(s). Anything could be suspected, can you lift the car on a jackstands and do visual inspection?
5. Air in the brake fluid.
6. Steering-related problem.

To eliminate the squeal, there seems to be 2 things you can do:
1. Install half-size pad shims on the rear brakes.
2. Apply molybdenum/silicone based brake grease. My rears used to squeal, even with the half shims. It was the application of cv-joint grease that terminated the squeal permanently.

Wait till other members jump in; people in the 850 forum are extremely knowledgeable & skilled. In the meantime, the following thread may be of some use for you:

https://volvoforums.com/m_48928/tm.htm

Time for me to go to bed. I'll come back tomorrow to see others' suggestions.

Regards,


JPN

 

Thanks, JPN!

I'll get out the Haynes manual and try and get under the car tonight. It needs an alignment for certain. The tires are new Kumhos so they should not be the cause. I'll mic the rotors and plan onreplacing pads and shimsthis weekend.

Tim

 

The half shims fix a sound from the rear, but not squealing. The sound if fixes ismore like you have a subwoofer in the back of your car and it's at reallylow speeds. Of all the Volvo's I've owned only the 97 needed the half shims, and they fixed the problem I described above.

I swear by OEM pads and either OEM or Brembo rotors. Any other pads have squealed on any of the Volvo's I have tried them on. fcpgroton.com or vovloparts.com have excellent prices on brake parts. good luck.

 

Hi Tim,

Glad to be of help.

As to the brake rotors, many European makes seem to use rotors that require replacement at every other pads change. Unlike American/Japanese makes, European brake rotors seem they're designed to wear IAW the pads, or they have less tolerance. So, I would replace the rotors too, when you do the pads. In general, machining/resurfacing the rotors is not recommended on Volvos. As JimKW (one of the most knowledgeable & most frequent posters) has noted, go with OEM.

http://www.fcpgroton.com/volvo850brakes.htm

Haynes states that you need to replace front caliper bracket bolts & rear caliper bolts whenever they're disturbed. I bought new bolts from FCP Groton (they're not on the list so you need to call them. One salesperson told me he didn't have individual bolt, whereas another salesperson was able to give me quotes on those bolts). I bought Brembo rotors and the 2 things I didn't like about them were that they didn't come with new caliper bolts (some rotors seem to come with new caliper bolts), and they were not made in Italy (they were made in Mexico).

When you do the alignment, I would do it either at a dealer or a shop that specialises in Swedish/European makes. The front suspension is of generic McPherson on 850s, but the rears are unique delta-link transverse arm design and generic shops may not be able to adjust them correctly.

Best wishes,


JPN

 

The OEM rotors do come with new bolts.

 

My Brembos didn't.


JPN

 

You guys are great! I won't run down to the Autozone for brake parts
The more I have to drive his car the more I can feel about it. I think the left shift is actually the front left caliper hitting before the other 3. The next clue is that it also releases slower than the other 3 so if you brake lightly it shifts left and then accelerating , it shifts back right as it releases. Strange. It has me wondering how good the hydraulics are on that corner. If the brakes are applied firmly it stops in a perfectly straight line with hands off the wheel. Panic stop braking is just fine too.

This car has both the low pitched howl and the screech when it stops...sounds like a city bus stopping. It will definitelyget half shims andOEM brakes. From what I can see the rotors look pretty good but I'll mic them and check for warpage this weekend.

Thanks again.

Tim

 

Glad to hear we're helping you.

I would also check for the minimum thickness of the rotors, if you have a measuring caliper. As to left brake caliper problem, it may be the piston seal that is getting tired, resulting in slower response than the other 3. If so, a rebuilt caliper may not hurt (though it does hurt your wallet). I believe FCP Groton carries loaded calipers (rebuilt calipers & pads installed).

http://www.fcpgroton.com/volvo850brakes.htm

It seems one front caliper is $65 with $30 core + shipping. I'll attach pics; the 1st one is the driver's side. Not sure if the pads are OEM but you can call them should you determine that the caliper needs replacement. You will also need about 2 quarts of brake fluid (DOT-4). I flushed my brakes with ATE's Super Blue Racing, as well as Motive Products' one-person pressure bleeder.

Thisseems to bethe original supplier of the rebuilt caliper:
http://www.beckarnley.com/

Wait till others reply again, regarding the possibility of left front caliper replacement; someone else may know a way to rejuvenate/re-condition the caliper.

Wish you luck,


JPN

[IMG]local://upfiles/6892/92CA308FB42F4E5BAD4828AA7A1D0C62.jpg[/IMG]

[IMG]local://upfiles/6892/9C8A17B14A224FE694E734F7DA381313.jpg[/IMG]

 

Problem solved! Thanks to all.

I finally got down to doing the brakes on my son's car. So far we only replaced the rear pads (rotors were OK) and used half-shims. It no longer sounds like a schoolbus when he stops and the pull to the left is entirely gone. The job should have taken a half hour but it took more like two hours. The old pads were way too thick. It took forever to get them out. After getting them out I compared them to the new ones and they were still 2mm thicker. The new ones slipped right in so reassembly took 5 minutes per side.

My theory is that the old pads were so big that they were not able to make full contact with the rotor (binding) on the right side to the car had that shift to the left feel. This weekend we will do the fronts and replace the fluid with super blue. Next... rear shocks. Sachs or Bilsteins?

Thanks again!

Tim

 

Hi Tim,

Glad the problem has been solved. Brakes are the most important feature of a car so you must be relieved that your son won't be having trouble with his brakes anymore.

As to the fronts, the caliper bracket bolts may be hard to turn, but I used a 3/8" drive breaker bar + 6-point shallow socket and they turned with not much effort. It was rusty, however around the contacting point between the bracket and the pads' tangs, so I put some WD-40 on a sandpaper and sanded them clean. I then put CV-joint grease at every metal-to-metal contacting points except the friction surfaces.The pad retainer springs may fight you a bit when you re-install them, but eventually you'll get a hang of it.

I myself went with Bilstein Touring and was happy with them. Sachs maybe about the same, but Bilstein Heavy Duty seems too firm. Whatever product you decide to buy, make sure to replace the upper mounts, as well as lock nuts for the bottom attachment. New shocks should come with upper lock nuts. To torque the upper nut, I used a Vise-grip to keep the piston from turning, and used a torque wrench with 3" extension + a crow foot. You kind of work at it an angle but should be ok. Or if you prefer, there is a special tool for this.

Let us know if you need assistance with front brakes & shocks.

Good day!


JPN

EDIT: When you bleed the brakes, make sure not to use an open-end wrench to loosen the bleeder screws. Use either flare-nut wrench orbreak them loosewith 6-point socket, then use open-end. I bought only one can of Super Blue, but you may want to get 2 cans just in case, as one can is just enough to do all wheels. I also bought a clear plastichose at ACE hardware to connect between the bleeder screws & a glass jar. I highly recommend that you also get one hose, 2~3 feet would suffice.