1995 850 wagon rotor life expectancy

[dosbricks]

If the caliper drags it gets real hot. It takes about 1 second for the pain from searing finger tip flesh to reach your brain - you hear the sizzling flesh before it hits. Ive tested this myself.

I use an IR laser pointed thermometer for this kind of research

[rdnzl]

Okay folks, research/testing reveals the following: not much.....

Both wheels spin fine - no noise. After a 20 min drive, taking pains not to use the brakes at all over the last 10 min (love my 5 spd), neither caliper feels hot or even warm. Left rotor slightly warm to the touch. By comparison, front rotors and calipers the same.

Interestingly, the front rotors (also new - maybe 2 wks) show clean, shiny metal in the swept area, w/ slight rust spotting outside of same , near the hub (it rained yesterday), while the rears are already starting to get the mottled look of the majority of the old rotor pictured.

From this, I deduce that there is indeed no contact happening, no polishing of the swept area. Agree? Both gentle and hard braking feel normal - hard to believe I'm only using the front, though, but I'll bow to general opinion here and swap out the calipers unless someone here steers me differently. Not looking forward to opening the system/wrestling with the apparently problematic feed line nut - I live by myself, so no help bleeding, and I've had enough of frozen nuts/bolts - don't ask!

Thanks for the help, and someone please tell me I don't have to replace the calipers

[dosbricks]

The rear rotors take longer to break in just because they only do maybe 25% of the braking and don't wear nearly as fast, but even a moderate drive around town on a regular basis would keep rust cleared off the swept area of the rear rotors if the calipers are working correctly and there is no air in the lines.

If you elect to do the change, you will need an 11mm flare nut wrench for the hard line on the caliper. Lowe's has a 3 wrench set reasonably priced which I found to be thick and strong. This particular tool is not one you want to acquire from Harbor Freight (if you read reviews). Soak the nut in PB Blaster for at least 24 hrs before you try to break it loose.

Rebuilt rear calipers locally sourced here were $30 each + COR charge. By getting them in town I could give the boots a good visual inspection before accepting them, and the COR refund was easy to take care of.

[erikv11]

If you want to avoid changing the calipers, bleed them first, just in case the problem is rear lines clogged or have air in them. You could get a power bleeder to bleed them by yourself. You'll need one anyway if you are replacing the calipers ...

[dosbricks]

If you want to avoid changing the calipers, bleed them first, just in case the problem is rear lines clogged or have air in them. You could get a power bleeder to bleed them by yourself. You'll need one anyway if you are replacing the calipers ...

+1
I use a Motive Power Bleeder and it makes the job a piece of cake.

[rdnzl]

One thought while whiling away the night hours: The reason I looked into changing out the rotors and pads is that I was once again, within ~ 1 yr. experiencing significant shuddering when braking, this after just replacing the front pads and rotors. Visual inspection of the rears showed what is pictured - similar to what the ones these replaced looked like - including the large black spots, which I interpret as being the cause of the shudder. But the problem indicates that the rear pads, at least some of them, were indeed contacting the rotor, otherwise no shudder.

A closer and perhaps more educated look at the old rotors show both have the black spots on the inside, none on the outside. The swept area on both sides of both rotors shows some definition, indicating at least intermittent contact by all four pads, but all four surfaces show a concentric/circular scratch pattern, not smooth shiny wear. Anyone with further thoughts?

[dosbricks]

Here are some rear rotors that look somewhat like yours.

http://volvo850wagon.wordpress.com/cate ... rake-pads/

Post #70 Rear Brakes/Deep Rumbling
Scroll down to the Safety Alert section. Then ask yourself if your Mechanic knows this. Do your own visual inspection.

[Jush]

Nevermind*

Although I noticed some uneven wear on the picture there, try sanding down your hub surface and leave out the little screw that holds the rotor in place, you don't really need it, and it may contribute to the uneven wear.

[SpeedyPete]

Hello all! Well I now have about 180K miles on my S70 and have gone through 2 sets of OEM rotors and pads ( those lasted about 20K each warp failure). Next went with Brimbo rotors they weren't much better (same warp failure 25K or so). On to Zimmermans which got me to about 110K according to my records before warp failure. And no I do not ride the brakes. They were all crap rotors. I then went to BrakePerformance.com and ordered their premium slotted/dimpled rotors front and rear. They come with pads and have had no problems since with warp failure. I do remember when first installed their was some drag from them however the break in period was about 500 miles or so. Problem free ever since I installed these and still stopping me fine. Regards, SpeedyPete

[rdnzl]

Greetings all. Took the old rotors to 2 different mechanics today - the one who services my truck and the one who services this car. Their opinions were unanimous: as long as the pistons compressed easily and I used a new pin set (they seated just fine - interesting post, though), I have done all I can to ensure the brakes function properly. Neither thought I had a caliper problem. Both blamed the short rotor life on a combination of cheap materials used in manufacture (recycled steel) and more importantly, the brine used hereabouts for keeping VT roads clear of snow and ice. The brine is apparently even more problematic than the old road salt. Both said they see this problem all the time. My Volvo mech said he has tried more expensive rotors, but they lasted no better/longer so he went back to a "mid range". Said if I get 2 years out of these ATE's to let him know, he'd love to find something better. Just FYI, these ATE's are made in PRC......guess I'll be asking more detailed questions at the next purchase rather than relying on forum recommendations, as I want to avoid Chinese rotors. That's making the assumption that Italian or American or other made rotors use better steel, which may well be a poor assumption.....

One other thought from this addled brain: if it's true that the rears only provide about 25% of braking force, and thus don't adequately polish off overnight corrosion from salt/brine, and that that's the reason VT rotors deteriorate so rapidly, I think I'll be changing my braking habits - at least in the winter - and using them considerably more and harder (when appropriate/safe) in the hope that I'll be polishing the surface better. Pipe dream? Perhaps. But it's worth trying.

So - I'm leaving well enough alone at least for now. Thanks for all the feedback.