Brakes are not exactly sharp and not very very reassuring

Try this:
run the engine and then turn it off. Immediately pump the brake pedal and count how many pushes it takes before it doesn't move down any more.

While you are at this point check the pentosin fluid level it should be just over the bottom of the screen. Color?

With a new bomb and a good booster it should take about 20 or more pushes to stop moving down at all.

If it doesn't move down very much on the first push then it is probably the booster or the new bomb is not properly charged.

Do you know what mate?? I give up with the standard brakes on my 840ci sport. Ive upgraded my discs and pads and still no joy.

I cant really knock bigger Calippers because I havent tried them but I will invest in a six pot calliper system and bigger discs for the front and better calliper for the rear which 8's allways suffer under hard braking.

The car weighs almost 2 tons. Mine is regularly serviced inc brakes but in general the standard brakes are rubbish. Im thinking of using AP braking a company in UK which Birds Hartge use.

The brakes on my 328 sport is much better and theyre standard. I think its because the 8's brakes are something to do with Hydraulics or something rather than servo assisted.

Anyone else with views on this??? coz im not quite sure.

My 840 brakes will put out all the pressure that my over sized tires feel like they can take. It is short of engaging the ABS on dry pavement but that is not a desired end anyway.

But in reality I really do very little motorway and when I do it is usually at speeds of 75 Miles per hour or less. The pesky roadside toll takers with badges have guns over here and get really scared and nervous when they get over 100 chasing you

I have found that the pedal seems soft but the braking action doesn't seem so. The soft pedal is the 3000 psi hydraulic booster internal plumbing to keep normal drivers from being smeared on the inside of the windshield by applying the brakes like it was a Chevrolet Impala.

Stainless steel brake line make the pedal a bit crisper by taking out the springiness of the original reinforced rubber lines.

Insuring that the operating pressures are correct and none of the hydraulic pressure relief valves are leaking could help.

Zitat

"joecarolan. ( the results)

I don’t believe BMW would produce a car with the class of the 8 series and put rubbish brakes on them.

Oh Yes they do, Go ask a e46 M3 owner how he likes his brakes

Most enthusiastic Owners change to AP Racing set up

I was informed by a very respected BMW tuning firm in the UK that 840 brakes will be "cooked" after 2 laps of any track day running!

Anyone with any thoughts on upgrades from maybe the new 6 series rather than the ridiculous sums wanted for aftermarket Brembos or whatever?

A cheaper option to Brembo/Ap racing is

http://www.hispecmotorsport.co.uk around £700 for the front set up

I only found out about these after I'd done the AP deal

Ok, so I've replaced all my discs (today actually) but I can honestly say I dont understand why the e31 brake system is a sore point. That said I only ever drive reeeeally fast on empty motorways and have never visited a trackday in my 8.

After my recent attempt at Go-Karting I doubt I'd be any good on a track anyway

I understand for aesthetic reasons why big brakes are 'needed' but I guess I'll never stretch the limits enough to wish I had them when braking. I dont doubt that stopping our 2 ton behemoths in race conditions requires an upgrade of some sort, but the car wasnt designed as racer so I guess BMW factor this into their design.

I had a 2001, E38 7 series with the same (front) calipers as a 1999 840Ci (black-enamelled BMW/Brembo), but when I first drove the latter, on first trying the brakes, I was concerened that the car wasn't going to stop. Certainly, a lot more pedal pressure was required than on the similarly-heavy 7-series and the pedal did not feel anywhere near as firm nor as progressive as on the 7-series. One big difference is that the 7-series had a vacuum-servo booster compared to the 8's all hydraulic system. I figured that the differences must be down to that. Then, I got a 1994, 850Csi and while the required pedal pressure is still higher that what would have been needed on the 7-series, at any speed, the stopping power is MUCH better than on the 840Ci and the pedal feel is also a big improvement. The brakes on the 840Ci were simply a big disappointment... And I tried several 840Ci and all were the same. But you do tend to get used to it after a few days. I'm not sure that it's down to the 4-piston calipers, as these same ones were employed effectively on the e38 and other cars with similar 4-piston devices (eg year 2000, MB SL) have had fantastic brakes. I think its down to the hydraulic boost system that's used on the e31. The CSi version has the same hydraulics, similar calipers, but it's better because of the larger discs. Having said that, when you really need the brakes on the 840, they do work, it's just that they have this feeling that does not inspire confidence... until you get used to it.

In fact, I was driving an e38 (728i) again over the last couple of days and couldn't help thinking how much better a car it is than the e31. Obviously, it doesn't look as nice, but the suspension is better (can take twisties at the same speed as an e31, but bumps are so much better absorbed); the steering is sharper with a more direct feel; overall better balanced, with lighter engine up-front; the cabin is quieter; seats are more comfortable; brakes are enormously better; the fuel guage doen't noticeably move; more space...etc.

Zitat

Is It not possible that I have a fault with mine or can anybody else confirm they get excessive brake pedal travel before you get the brakes to respond, and even then you have to push fairly hard to stop the car.

My brake booster was leaking a while ago, and I had exactly the same problem. I only drove a few km to the dealer with the park brake in my hand, ready to do some emergency braking. Good thing I didn't need to. The dealer put in a used brake booster (with waranty and way cheaper than new) and everything has been fine ever since.
Comming friday I'm getting new discs front and rear. I'll post some pics here later on.
http://www.autopartsonline.nl/…41&width=1280&height=1024

Peter

Zitat von joecarolan

I will look at upgrade options and search e31 for ideas and other members successfull solutions.

Should be getting my car back today/tomorrow with the new Disc/Pads/Caliper/Braided Hoses on. I will post comment on performance when I get my keys back. I should notice some difference, if only because everything is new.

Zitat von joecarolan

.....to improve my e31 brakes pedal pressure and sensitivity and faults that possibly don't exist..... .

I think that although they don't have the best pedal feel, it's just how they are and it's a case of getting used to them. After driving the 840 for a while, the brakes on the e38 felt a overservo'ed.

I would still check everything, however, for peace of mind, but if your pressure reservoir gives you a good reserve (about 20 pedal operations with the engine off) and you have checked the calipers, hoses, pads and discs, then that's it.

brakes

See some people may argue that they're not all that bad but this is merely my opinion......
When youre in a driving mood and you come to a corner at speed and want to brake hard the 8 series is every where especially when you get idiots in other cars trying to race you to prove a point. I think the braking system on my 840CI SPORT is awfull. My E46 328 saloon out performs in this department everytime. My wife drives a 1994 merc SL320 and the brakes on her car are Phenominaly good. And its almost a two ton car too.

Im sorry but BMW just got it wrong with the brakes on the 8.
I never let anyone knock down the 8 but this is something I would not debate on because BMW could have done much better. All that money invested in safety ASC DSC etc when they should have been spending more money and effort on producing a car that stops.

I had a race with a VW VR6 once and soon as we were approaching a sharp bend I had to slow down earlier where as the Golf braked late and allways had an advantage.

I will definately be investing in an AP brake set up very soon.

Does anyone know of a better set up where you can notice dramatic improvements????

I think the brakes on the 8 fade too quickly. What would be ideal is ceramic discs and the biggest callipers you can use inc QUALITY brake pads produced to take a beating under hard braking and virtually fade free like the brakes on the Merc AMG SL range.

Re: brakes

Zitat von bimmerman840ci

.....My wife drives a 1994 merc SL320 and the brakes on her car are Phenominaly good. And its almost a two ton car too.... .

Yes, I did mention earlier in this thread that the SL brakes (also an SL320) were fantastic in comparison.

It's strange that even on late-model 1999 840Ci the brakes were not improved, even to match those on the e38, which came out in 1994. The brakes on the CSi version are significantly better and these too could have been used on later 840 models.

Just got some new discs and pads. The're not better than stock, but not worse either. I needed new ones and they look better and are cheaper.

very smart. what make are they by the way?

was supposed to get mine back today.... but still waiting on parts. No car for weekend