Couple of questions on the front brakes:

1) I've got a little shimmy when braking only that I've had for awhile which leads me to think I've got a little warped rotor issue. I've done quite a bit of front end work recently (control arms, bushing, center link, etc) so I don't think it's a suspension issue.

Before I order a set to replace them, I just wanted to make sure there's nothing out of the ordinary about them (like wheel bearings packed in them, or something like that). I assume they just sit on the hubs and there's nothing fancy about swapping them out.

2) I've read on previous posts about the progression of brakes through the model years. If I understand correctly later model 840's received 4 piston Brembos while the later model 850's did not. Is that correct? If that's true, I'd love to know the logic of why a car with a heavier nose had less capable brakes...

The previous owner of my 850 installed the Brembo branded 4 piston capilers. Are those the same model as the 840 factory brakes (therefore I can order replacement pads designed for the 840) or are they not the same unit?

3) Finally, I'm tired of brake dust and in the market for some ceramic pads (I think). Any recommendations on products in that space?

Thanks

Couple of questions on the front brakes:

1) I've got a little shimmy when braking only that I've had for awhile which leads me to think I've got a little warped rotor issue. I've done quite a bit of front end work recently (control arms, bushing, center link, etc) so I don't think it's a suspension issue.

Before I order a set to replace them, I just wanted to make sure there's nothing out of the ordinary about them (like wheel bearings packed in them, or something like that). I assume they just sit on the hubs and there's nothing fancy about swapping them out.

2) I've read on previous posts about the progression of brakes through the model years. If I understand correctly later model 840's received 4 piston Brembos while the later model 850's did not. Is that correct? If that's true, I'd love to know the logic of why a car with a heavier nose had less capable brakes...

The previous owner of my 850 installed the Brembo branded 4 piston capilers. Are those the same model as the 840 factory brakes (therefore I can order replacement pads designed for the 840) or are they not the same unit?

3) Finally, I'm tired of brake dust and in the market for some ceramic pads (I think). Any recommendations on products in that space?

Thanks

You definately are correct about the later model 840's having the 4 piston Brembos from the factory. I guess the 850 didn't have it because along with ABS, they also had hydraulic power brake assist as well as the front vented disc, so during that time, it was almost more than enough stopping power. I have no idea if the 840 brakes and your brakes are the same, but you could still probrably order the 840 replacement pads since yours are 4 piston and almost close to the factory brembos specs if not exactly the same. I can't help you with the shimmy feeling when braking, but PM Mr. Cradick (rcrad6653) because he has loads of information on this type of stuff.

Sorry to hear about the issue and good luck.

All the 840's got the 4 piston Brembo calipers and is probably the first thing to go on a parts car for an upgrade to the V12s. I wouldn't think the aftermarket version uses proprietary pads, but am not certain. I'm sure people will chime in with their preferences of pads and why. For my front refurb I'm just going with OEM Textar. There are aftermarket rotors all over the net at attractive prices, and people will relate their experiences with those. Stock rotors are Balo, and I personally would only put on Brembo or Zimmermann X-drilled if aftermarket. I have a set of new Balo that were drilled and plated (standard is raw undrilled). Though not needed at this time, I will rebuild the Brembo calipers anyway to new condition and paint the bodies for a nice clean look, add stainless lines, new wear sensors and pads, done..... for about $250 a side.

2) I've read on previous posts about the progression of brakes through the model years. If I understand correctly later model 840's received 4 piston Brembos while the later model 850's did not. Is that correct? If that's true, I'd love to know the logic of why a car with a heavier nose had less capable brakes...

The previous owner of my 850 installed the Brembo branded 4 piston capilers.


All M73 engined E31 had Brembo 4 pot front calipers, Your '96 came stock with them. The change was made about the same time the 840 was introduced.

Contrary to popular belief, the Brembos actually have LESS braking ability then the single pot calipers. The only reason BMW used the Brembo caliper is because it is much lighter and cuts the "unsprung" weight and impoves steering sensitivity.

People who have replaced the single pot calipers with 4 pot calipers and those that will in the future will notice a bit more pedal travel (unless the master cylinder is changed which will require a change of the brake booster as well) as the 4 pot caliper requires a higher displacement of fluid for movement.

I like Rotex Gold pads, they're dustless but quiet; and they're semi-metallic meaning that they will not eat your rotors. These are the best pads

that's some great info ed. thank you

But your vibration is likely to be your thrust arm bushings saying good-bye. I note that you say you've done some work on the front end 'recently'. How recently? (time, miles, type of roads, speed) How did you tighten the bushings?

Gerry has a nice poly bushing set avail via wuffer.

All M73 engined E31 had Brembo 4 pot front calipers, Your '96 came stock with them. The change was made about the same time the 840 was introduced.

Contrary to popular belief, the Brembos actually have LESS braking ability then the single pot calipers. The only reason BMW used the Brembo caliper is because it is much lighter and cuts the "unsprung" weight and impoves steering sensitivity.

People who have replaced the single pot calipers with 4 pot calipers and those that will in the future will notice a bit more pedal travel (unless the master cylinder is changed which will require a change of the brake booster as well) as the 4 pot caliper requires a higher displacement of fluid for movement.

Interesting... I need to research this some one evening or this weekend. If the M73 came with Brembo 4 piston calipers already, it sounds like there wouldn't have been a point to install the Brembo kit.

This is what I though I had (except my calipers are black with the Brembo logos on them).... http://www.brembo.com/CatalogoHPGT/DetailPages/KitDetail.aspx?id=1B4.7001A&idLingua=1

Now though I think I need to pull the wheel off and do some closer inspection...

But your vibration is likely to be your thrust arm bushings saying good-bye. I note that you say you've done some work on the front end 'recently'. How recently? (time, miles, type of roads, speed) How did you tighten the bushings?

Gerry has a nice poly bushing set avail via wuffer.

Last spring was when the front end work was done, about 7,000 miles ago. Drive 90% interstate or state highway miles.

I didn't do the work, a local mechanic did.

All M73 engined E31 had Brembo 4 pot front calipers, Your '96 came stock with them. The change was made about the same time the 840 was introduced.

Contrary to popular belief, the Brembos actually have LESS braking ability then the single pot calipers. The only reason BMW used the Brembo caliper is because it is much lighter and cuts the "unsprung" weight and impoves steering sensitivity.

People who have replaced the single pot calipers with 4 pot calipers and those that will in the future will notice a bit more pedal travel (unless the master cylinder is changed which will require a change of the brake booster as well) as the 4 pot caliper requires a higher displacement of fluid for movement.

Interesting info ...

Does the same hold true for the upgrade of an early 8 to euro csi front and rears... calipers/rotors/pads?

-JRW

One thing is for sure, the arms need to be pre-loaded prior to tightening them. This is imperative otherwise the bushings will tear up. Most mechanics will not pre-load, so hopefully your mechanic knew about this very important step.

Interesting info ...

Does the same hold true for the upgrade of an early 8 to euro csi front and rears... calipers/rotors/pads?

-JRW

No, even thou the clamping forces will be nearly the same, the biggest improvement using the Euro CSI brake system is the increase in rotor diameter(s) that has the net effect of increasing the leverage arm. Of course there are other advantages with a larger rotor, there is a greater mass to heat which will take longer (it will take longer to cool as well but it is a benefit for larger mass.

If you have the Brembo Grand Tourism front upgrade brake/caliper set #1B1.7009A1 ($2875), no, the replacement pads for the factory installed Brembo will not work. The pads are shaped differently. When I replaced my pads I used Hawk HB 193F.670 ($121 from Tire Rack). I wouldn't recommend ceramic pads unless you are a hard core racer.

Love them 2 piece rotors...

Last spring was when the front end work was done, about 7,000 miles ago. Drive 90% interstate or state highway miles.

I didn't do the work, a local mechanic did.

Recommend inspection of the bushings. Many mechanics don't know that the bushing only should be clamped (bolt tightened) with the wheels fully on the ground. If this is not done on the ground, it reduces the life of the bushings.

One thing is for sure, the arms need to be pre-loaded prior to tightening them. This is imperative otherwise the bushings will tear up. Most mechanics will not pre-load, so hopefully your mechanic knew about this very important step.

I looked at the bushings... while new looking still, they did look a little torn in spots. I haven't replaced them before... can you remove them while loaded (like driving the car up on a ramp), remove, replace, reinstall, or do you have to have the car lifted from the body to remove and replace?

If you have the Brembo Grand Tourism front upgrade brake/caliper set #1B1.7009A1 ($2875), no, the replacement pads for the factory installed Brembo will not work. The pads are shaped differently. When I replaced my pads I used Hawk HB 193F.670 ($121 from Tire Rack). I wouldn't recommend ceramic pads unless you are a hard core racer.

I have the one piece rotor. I'm looking at my caliper though, it looks similar to yours, but is that the same caliper that come's stock (just without the logo)? The rotor looks like the stock size to me, so I wonder if really the rotor was all that was changed. There's no stainless steel lines on the car, which I assume comes with the full kit.

Also the brakes have recently gotten quite squeaky, but it looks like the pads have decent wear on them. Any suggestions there?

I looked at the bushings... while new looking still, they did look a little torn in spots. I haven't replaced them before... can you remove them while loaded (like driving the car up on a ramp), remove, replace, reinstall, or do you have to have the car lifted from the body to remove and replace?

Sounds like they are toast. The OEM are filled with special fluid that may be gone by now.

You can check with a crowbar just how flexible they are. There should be some give but overall they should be firm.

Vehicle has to be lifted to replace. Easy DIY. Best to have ball joint puller as to not damage the ball joint on the arm. Don't use picklefork - unless you want to replace arm and steering box (over time) as well.

Any suggestions there? You should consider the SS brake lines, A lot less brake pressure needed to stop the car, You getting even pad wear on all four front pads? What type of pads are you using? I never heard a textar pad squeak which is what i use but they provide more dust cause there soft.

**The picture that shows the pad looks a little warn** You think the sensors are rubbing causeing the squeak?