951 Brake Upgrade

[Thom]

I don't want to hijack the thread but how we get rid of brake lag when installing larger calipers?
I like my Big Blacks but having to pump up the pedal once to load them is getting a old.

[chris white]

I don't want to hijack the thread but how we get rid of brake lag when installing larger calipers?
I like my Big Blacks but having to pump up the pedal once to load them is getting a old.

it shouldn't require any pumping - perhaps you have some rotor run out?

[Latitude48]

I don't want to hijack the thread but how we get rid of brake lag when installing larger calipers?
I like my Big Blacks but having to pump up the pedal once to load them is getting a old.

It shouldn't be a problem since the piston sizes on the big blacks are the same as the 951S. I don't have any issues with the big blacks in my s2. Will be interesting to see what others think.

[ROB III]

Thom, do you have a pulsating pedal and any steering wheel shimmy? My son's 5 Series wagon had a terrible runout problem with steering wheel shimmy and pulsing pedal when the brakes were applied, we installed new rotors and flushed the old, grungy fluid out, filled with fresh fluid and new pads and bled again to get air out, problems gone with a firm pedal. When was the last time you checked the fluid level? Any evidence of leakage anywhere? How old or worn are the pads?

[Thom]

Everything checked out OK, except last cause I can think of is worn out spindles causing run out of the complete hub/rotor assemblies. I don't understand it however as the bearings are not very old and I couldn't feel or see any wear on the spindles when I replaced them.

[chris white]

Usually it’s the hubs, especially the 86 hubs when you seat the bearing races. The spindles are steel - hard to screw up and when they fail they snap. Hub are aluminum- they can get screwed up in any numbers of ways!!!

[Don_Cote]

Simple answer is…nothing! 86 was an odd offset, one year only. You can get special kits for it ( not cheap) but you could also consider changing to later (87+) offset. Much better choice of wheels, better rotors and easier brake upgrades

How hard is it to upgrade to the later 87+ offset spindles ?

[Don_Cote]

Hello, i went with 87+ spindles, 996TT calipers and 996 gt3 front discs with an adapter.
The 86 spindles are weak if you want to track with slicks etc.

Erik

I like that idea, it sounds like I should switch to the 87+ spindles and then I would have more options.
thanks

[Don_Cote]

Hello, i went with 87+ spindles, 996TT calipers and 996 gt3 front discs with an adapter.
Erik

Looking at your picture it appears the 996TT calipers don't have the depth to completely cover the GT3 rotors, so whatever adapters you used places them at the outer edge so you gain swept area vs 996TT rotors? If so, then you should have more "stopping power" as Tom put it compared to big red/black calipers and rotors.

The 996TT is 330mm vs 350mm on the gt3 discs.
If they don't hold up, I'm switching to 997calipers, Giro disc and ebc rpx pads.

The oem 951 brakes did not survive track days, even with big cooling and full race pads.

What would I have to do to switch to either the 996TT calipers or the 997 Calipers once I upgrade to the 87+ spindles. Is the required adapter readily available ?

[Tom]

I'm inclined to go with something tried and true, like the Big Red kit paragon sells...

https://www.paragon-products.com/Big-Br ... 4bbk_2.htm

Need to update the offset too though, so it goes on the list for now....