Just changed my front rotors on my 91 740. They dont squeek as much and it is much smoother the stop. But it feels as if the car is pulling more then ever, it may just be in my head, but id like to get your thoughts.

 

Are the caliper sliding pins moving easy?

 

I don't think im sure what you mean tech.

 

Here's a couple of pics for ya colgate depending on whether your calipers are single or dual piston. The pics show the guide pins (sliders) of which the caliper assembly slides back and forth on.

 

Thanks for that! Yeah, the guide pins went in fine and are nice and snugg.

 

The car should never pull when stopping. Or any other time if the road is reasonably flat. The pins are supposed to be snug in the stationary part but should move smoothly in and out of the piston portion. (I could have that backwards but one unit definitely moves smoothly.) Failure to do so will cause the caliper to drag causing pulling in the steering and uneven wear on the pads (more wear on the movable pad). A caliper with well lubricated pins should wear the two pads evenly. The common failure mode of a caliper is leaking (obvious) or sticking (which shows uneven pad wear). Sticking is caused by pin friction or a stopped up brake line, particularly the rubber portion that connects the caliper to the steel portion. Both of those sticking problems can be fixed without replacing the caliper. A dry unit with evenly worn pads (both pads equal thickness) is almost always good. I don't hardly know of a brake man that ever met a caliper he liked, however. They frequently want to replace them = high bucks.

Likewise with rotors. If they aren't causing the steering wheel to vibrate when stopping, they generally don't need replacing or even trueing in my opinion. That last one is debatable and opinions vary but I've quit having rotors cut and the only ill effect is probably slightly accelerated pad wear while the pads wear into the slightly uneven rotor surface. Of course you may have to replace them if you've let the rivets grind an eighth of an inch into the surface on one side.

Just check those pins for lubrication and make sure that collapsing the piston (with a C-clamp) readily pushes fluid back into the master cylinder (clear brake lines). You've already done that last part if you replaced the rotors. Good luck.

 

I need to replace the rearrotors and pads on my 99 S70. I have replaced both sets of pads on both my BMW's myself. It was easy. How difficult is it do change the rear break pads and rotors? With BMW I find all kind of dyi info available (step by step procedures). Is this info available somewhere on this site or another site?

 

I just replaced the rotors and pads allaround on my 740 gl. I can say the rears were even easier then the front. It had more to do with the fact that the rear pads are smaller, easier to put in, and that the bolts holding the caliper to the axle are regular bolts vs. thehex bolts in the front. But basically they were exactly the same.

ALso these rotors don't get into the hub like my ranger did. so no greasing wheel bearings. there is a small alignment bolt that you remove after calipers and the rotor comes off real easy. The bolt was 10mm. btw the front hex bolts are 10mm as well. at least for the rotors for a 14 in wheel.