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Volvo 850 S70 Front Brakes

Published on January 25, 2011 by Bay13

Just a few general things to mention prior to starting a front brake job. Look at the brake fluid reservoir and make sure it is at a level that will allow for the collapsing of the two front calipers, I have found that in between the min and max line is more than enough room. The brake fluid should be DOT 4. The part number for the front pads is 271859. The pink silicon grease is part number 1161325. If you are replacing the rotors make sure you specify 4 lug or 5 lug rotors (the older 850 has 4 lug). You will also need a can of brake cleaner to clean surfaces you will be putting the silicon grease on. As far as tools, you will need a pair of needle nose, large channel locks, 7mm hex, 15mm socket, and a 10mm socket, a hammer to help break the rotor loose and a wire brush to clean the rust off the hub prior to putting the new rotor on. The pads in the below pictures are 12mm new and need replacing at 3mm. The Volvo rotor new is 26mm and should be replaced when only 23.8mm is left. Normally you will get two sets of pads to one set of rotors. You can keep your eye on pad wear by comparing the backing plate (5mm) to the remaining pad. You can usually get a good enough look through the spokes of your wheels.

Above is a new set of Volvo pads, also the retaining spring, black plastic caps for the slide pins, a 15mm socket and 7mm hex socket. The top two pads are the outside pads and the bottom are the inside. The inside pads have the clips on the backing plate that snap into the caliper. Notice that the actual pad surface on the bottom have tapered edges and the top doesn't, this is something new and I haven't found an answer yet. Below shows the slide pins, retaining spring and caps.

Above is the right front brake assembly. To start you have to remove the retaining spring on the caliper. I use a pair of needle nose that have the curved nose. Pry out the spring where the yellow arrow is pointing, and once out, you can move the spring to the left a bit and pry the top out. When putting the spring back in, put the top in and then set the bottom on the hole and pry the spring around. This can be a challenge. If you will be changing the rotor the 10mm stud will have to come off (red circle).

The yellow arrows are the black plastic caps that have to be popped off to get the (7mm) hex slide pins out. If you are doing the rotor the 15mm bolts have to come out to remove the pad retaining assembly. (Pink Circle) Don't remove the 15mm right now. Once you have the two slide pins out, they need to be cleaned and greased for replacement later. Now you can wiggle the caliper back and forth to collapse the caliper a bit so you can lift the caliper off of the rotor. The inboard pad will stay attached to the caliper and the outboard usually stays in place.

The above picture shows the pads removed, caliper collapsed (use channel locks and squeeze it in), cleaned and greased with the silicon grease. If you are only doing the pads, this is a good place to rest the caliper, however if you are going to remove the rotor, I use a bungie cord and hang the caliper from the front strut spring. If you are taking the rotor off wait on the grease job. To remove the rotor from here, secure the caliper, remove the 15mm bolts and set the pad holder out of the way. Remove the 10mm stud, and use a hammer to break the rotor away from the hub.

Now that the rotor is off, take your wire brush and clean off any rust or build up on the hub mating surfaces. Clean your new rotor, and mount it on the hub with the 10mm stud. (Not too tight its easy to break the stud) Grease up your pad holding bracket, (it's really part of the caliper, but holding bracket is more descriptive) slide it on the rotor and secure it with the 15mm bolts (100 Nm).

The above picture shows pads greased (backing plates), now flip the caliper back down and push it over the rotor and shove it into place. Insert the greased 7mm hex slide pins and tighten them to 30 Nm, snap the black plastic covers back on. You might want to take the time to grease the steering stops now. Last step is to put the retainer spring back on the front of the caliper and then you are done.

How to remove and install the pad anti-rattle spring

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