PeteB » Link to Volvo Brake Service manual: http://www.volvotips.com/index.php/850- … ir-manual/ I repaired our 1996 850 rear brakes back in 2014 when it was making loud rumbling noises. I started to write here that the caliper pistons were frozen, but actually the pads were rusted frozen in the slide area so that only one side pressed on the rotor, probably causing the rumbling sound. Documented in this old thread: viewtopic.php?f=1&t=65446 Summary here: viewtopic.php?f=1&t=65446&p=442588#p442335 We did the following at that time:
- 1. Rebuilt uncoated Cardone Calipers from FCP and new NAPA Premium rotors.
- 2. New cheap pads from NAPA, replaced about 20K miles later with NAPA Premium
- 3. Cheap Hardware kit from a local auto parts store, later replaced with Volvo hardware. We ended up using the original Volvo pins with the cheap hardware kit since we could not get the new pins supplied to seat. If I were doing this again and could not get OEM/ATE hardware I’d just clean up the original hardware and reuse it.
- 4. People talk about the half shims between the pad and piston preventing the rumbling but they were there in our application and did nothing to help the situation. The latest version of the Cardone rebuilds have pistons where half of the face steps down about 1/16″ which I believe accomplishes the same thing as the shims with older flat face pistons. Not sure about this but will try them without half shims.
WARNINGS
- 1. Pins from most of the aftermarket hardware kits do not fit properly, the retaining ring is too large as shown in detail here – see 6/14/14 safety update: https://volvo850wagon.wordpress.com/category/brakes-2/ Note that he found that the Duralast brand hardware kit fits and looks exactly like the ATE kit that I just bought in 2017 so it might be fine. Picture showing incorrect pins vs. OEM: https://volvo850wagon.files.wordpress.c … cn3336.jpg
- 2. Most of the aftermarket retainer hardware does not fit properly often touching the caliper rather than the pads – use original ATE hardware that is now cheap at FCP and fits properly.
- 3. The original Volvo pins will fall out if you do not tap them in with a punch below the surface of the caliper. I know this from experience.
Now in 6/2017 the rebuilds are also frozen even though I have inspected, cleaned and greased them about once a year. One side has excessive even wear on the pads with only 1/3 left, the other side has one pad looking nearly new and the other with only about 1/3 left. My theory is that the flex hoses are partially blocked so that the pads drag for a long time after application causing them to overheat, rapidly rust, and fail. I’ll post pictures soon of the massive amount of rust on these calipers.
I was at FCP returning the front caliper cores and also showed them the frozen rear calipers from 2014 which they replaced no questions asked! I even brought the OLD DOT 4 used brake fluid from 2014 which they also replaced for free!
Photos
Picture of the Cardone caliper installed in 2014 as it looks 6-2017:
Older, probably original Volvo caliper from 1996, note that the pad is seized into the slide area due to the massive rust. Also note how much more rust there is on the side that seized and dragged, probably due to higher temps: Note that the lower shoe has uneven wear due to the half shim, this suggests that as the shoe wears the half shim becomes less effective as some have noted on here.
The next picture shows a variety of “anti-rattle” hardware, first with the rivet is the original from 1996, next is 2014 purchased from Volvo (about $40 with pins), next is 2017 ATE OEM, and final was included with the 2017 Cardone calipers and does not fit reliably. One just barely fit the other was too wide, the extra width is visible by eye. I used the 2017 ATE OEM kit from FCP and it fit properly:2014 Volvo hardware test fitted to show the clearance of about 1/16″ on each side:
Next pic shows new rebuilt Cardone with included hardware. It did not fit and I bent it as can be seen to make it fit – still it is not right, so we bought new ATE OEM parts:
This is the other hardware included with the Cardone that DOES fit but with nearly zero clearance:
ATE OEM kit installed in both new/rebuilt calipers:
ATE OEM KIT, cheap at FCP, note the correct and too large pins below:
