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View Full Version : Brake line question for 840 caliper people...



mancini_mark
01-22-2010, 02:28 PM
Ok, so I found a set of 840 4-pot brembos for the front and I am running 91 M5 rears. I am looking for a set of braided stainless brake lines to go with. Do my 525 brake lines just scre/fasten into the 840 calipers, or do I need something special? So am I ordering the line set for an e34 or half E34 half 840?

Bruno's site seems to suggest that it's a direct bolt/screw on upgrade?

Thanks.

mancini_mark
01-22-2010, 06:47 PM
RealOEM is showing the same hose number for the front of the 525 and 840, so I ordered a Stoptech set. We shall see.

Tiger
01-22-2010, 10:23 PM
Yes, let us know what is the end result... I think I will change out the factory brake line with new one since it is already 16 years old.

BigKriss
01-25-2010, 07:28 AM
yeah i think the brake fitting ends should be the same

Ferret
01-25-2010, 07:52 AM
Choose your stainless lines very carefully, I've just been reading something interesting over here:
http://forums.bimmerforums.com/forum/showthread.php?t=1386172

bubba966
01-25-2010, 02:15 PM
I wouldn't put SS brake lines on a street car.

They're meant for race car use to protect the lines from being damaged by track debris. They also need to be frequently inspected and changed more often than stock style rubber lines. They are prone to abrasion bursting, as well as separating at the fitting. Not a problem when you inspect your brake system before every race (after what, an hour or two's worth of use?). Do you pull your wheels off after every couple of hours worth of use and inspect your braking system? If no, stick with stock rubber lines.

mancini_mark
01-25-2010, 04:47 PM
Ooh. Read that stuff on the other forum. Ebay crap. I spent the dough on the Stoptech lines from BMP. They are specifically desigend to swivel and not bind like that. My car isn't a daily driver anymore. I might take it to work on a nice summer day, but it will probably see more autocross and track time than street time this year. The BMW club requires us to have the car inspected and certified prior to the track days. For the other stuff, I will have to pay a bit more attention.

Thanks.

Mark

bubba966
01-25-2010, 07:00 PM
Stoptech lines will burst as well, just not pop apart at the joint like that one did. If a Stoptech line goes, it's above the crimp where it fails.

I forget, are the Stoptech lines coated/encased or are they bare stainless flex? Bare stainless lines will get sand/grit underneath the stainless and wear at the line until it bursts.

And do the Stoptech lines have factory style mounting points on them? I don't recall if they do or not (sorry, I quit paying attention to each manufacturers lines after I found out the various ways they fail). But you need to make sure that the lines are mounted just like the factory rubber lines are mounted so that they don't contact things and rub through. One of the local CCA guys had his nice (Stoptech as I recall, and he couldn't get them to replace it at all) SS lines fail like that. Lacked the factory mounting and would rub on the fender liner. As it wasn't a track car the lines weren't frequently inspected and it burst at the rub point. Lucky for him him wasn't going very fast when it happened and was able to limp it home with the parking brake.

Just remember to keep a good eye on the SS lines when you install them. It doesn't matter how well they're built they won't last as long as factory rubber lines do.