[333pg333]

Hi Guys. I'm looking at making my brakes less mushy (too soft + too much travel). I've considered the upgrades that everyone normally does aka Big Red/Black but I'm not convinced this will solve my problem. Possibly make it worse due to extra unsprung weight. I thought that it was the master cylinder that needs attention instead. I've done a little digging but would like to hear from anyone who knows or has done this sort of upgrade? I was advised to check out : http://www.tiltonengineering.com/ by Karl from RacersEdge who has one of their kits on his S2. Oh by the way I'm not a brother, more like a cousin to you guys. ie '89 944 turbo 's'. However the principle's the same. I have the large 4 pot Brembo's from the 928 S4 w 968 underbody air deflectors, s/s braided lines, $$$$ racing fluid, and have been using EBC yellow pads although I'm upgrading to PFC 01's and 97's. Any advice or experience is greatly appreciated. We do mostly short SuperSprints on circuits with hard braking for short durations. 3-6 laps.

Thanks in advance.



Patrick

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[Jim Child]

My race car does just fine with a stock master cylinder, and believe me I use the hell out of the brakes. My calipers are the same as yours, I use full race pads, Motul 600 brake fluid and cooling ducts. My pedal feel improved significantly when I switched from ATE fluid to the Motul. What fluid are you using? I do replace my master cylinder every now and then with a new one as a maintenance item. Is yours the original one that came on the car?

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[cooz]

my 968 pedal was also too mushy with more travel than i like.



it's much improved now that i have brake cooling ducts, PFC brake pads (01's) and Castro expensive racing brake fluid.





Norm Mandell

94 968 race/track car

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[Clem]

I have the same problem, currently using ATE and KFP Golds with the S4 brakes

I'm going to do a full flush of current ATE to replace with SRF (Norm, I have a ton if you need some).

I'm also planning on trying some Pagid Blacks and PFC97s - I think the KFPs are just not up for racing conditions.



I have heard that a lot of air can get trapped in the abs system. I am going to work to try to get all this out (not sure exactly how) and see how that changes the pedal feel.



I still have the stock brake scoops, and if the above does not work - I'll upgrade to better ducting.

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[Eric_K]

Going to bigger calipers won't firm up the pedal, probably more the opposite. The stock master cylinder is perfectly capable of giving good feel. It sounds like there is air trapped in the system or the mc is on the way out.

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[968gene]

my $0.02, we used Ford Truck Brake Fluid on our race car. We had dialed out the rear brakes and were only using the fronts (circle track racing). The front brakes and the fluid took a beating. We changed the fluid after every race. The Ford stuff is fairly inexpensive. My understanding about master cylinder upgrades is that they might improve the feel of the pedal, but they often don't upgrade the performance.

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[333pg333]

[quote name='Eric_K' date='Sep 21 2006, 01:17 PM']Going to bigger calipers won't firm up the pedal, probably more the opposite. The stock master cylinder is perfectly capable of giving good feel. It sounds like there is air trapped in the system or the mc is on the way out.

[right][post="26296"]<{POST_SNAPBACK}>[/post][/right][/quote]

How do you determine that your brake cylinder is on it's way out. It still seems to function reasonable well in daily driving. It even pulls me up on the track ok but there are definitely times when it just seems to almost go to the floor and you really have to stand on it, yet it still actually does pull me up. Weird. Also I've just ordered a rear brake bias valve to send a bit more work to the rear. Totally opposite to what is set up for the circle track apparently?

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[cooz]

if your pedal is good on the street but becoming low on the track....i'd guess it's because your overheating your rotors/pads or most likely the brake fluid...



as i said in my earlier post.....i had this problem as well and fixed with brake ducting hoses, PFC pads and castrol srf fluid.



norm

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[Jim Child]

It sounds more to me like you've got air in your system. If it were me, I'd go ahead and replace the MC with a stock unit just to be safe and rule it out of the equation. Its not that expensive and its an important safety/maintenance item. I'd then thoroughly flush the system with either Motul 600 or Castrol. Motul works fine for me, and because it’s a lot cheaper than the Castrol, you can flush as much as you want. I'd run at least a litre though it, and then run it hard on the track, and then run another litre through it.

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[333pg333]

I'm sure that is the same fluid in the car and the brakes have been bled frequently. The car has the underbody air deflectors which have been an improvement and I will go to the PFC pads soon. If there's a fault with the m/c should it not show signs of seepage? I will look for them around the brake actuator. I think I'm going to swap out the m/c for a new stock one and see if that helps.

Thanks for the responses guys.

Patrick

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