Pedal Pump Up?

[volcomamskater]

I know there are faq's on how to fix this, but could someone explain it a little better on how to fix it for good? Any help is appreciated. thanks

[volcomamskater]

Sorry, I have a 97 gst with a act 2100 clutch, new master and slave cylinder's aws well.

[Jakey]

Do you still have the OEM rubber clutch line?

[volcomamskater]

Yes, I still have the oem lines, where can I get upgraded replacements? I know the faq's say to adjust your pedal travel, but I don't see how that could afect a hydraulic system? Because wouldn't you still be putting pressure into the system, and it would still somehow not be relaeasing all the pressure?

[Onefast99gsx]

To fix mine for good, I changed the Master cyl, slave cyl & installed a SS braided clutch line. For the heck of it, I also put on a new clutch fork and pivot ball.

If you have a 2g, this is the infamous 2g pedal pump up.

Taken from RRE's site:

If you are fighting an inconsistent pedal adjustment in a 2G, adjust the upper pedal stop adjuster so that you gain additional free play at the top of the pedal travel. If this is your problem, you will notice that the pedal suddenly gets very tight and the release point will suddenly move up a lot, this is the cause.


2Gs need free play at the top of the pedal travel. If it is close to no travel and right on the edge, then it pumps up. Only 2Gs have a relief valve in the master cylinder that needs to be uncovered so fluid can go back into the reservoir on the clutch release. If not, it gets tighter and tighter and tighter. Then it may slowly relieve the pressure and it is back to normal. Just a 2G thing. You need more free play at the top of the pedal travel.

Left unchecked, the pedal will pump up more and more. The clutch will begin to slip since it is as if you are driving around with your foot on the clutch pedal. Also it plays hell on the crankshaft thrust bearings. The constant pressure pushes the clutch release bearing onto the clutch and flywheel. When centrifugal force throws the clutch release fingers outwards, they make additional pressure on the thrust bearings of the crank. This is an additional factor in short lived crankshaft release bearings and an additional potential cause for crankwalk.

[Jakey]

where can I get upgraded replacements?

Well you could either have one made, contact any of the site sponsors, or call one of the major DSM vendors (Buschur, RRE, etc.). I got mine from Buschur.

[1ViciousGSX]

All you need is to have the clutch pushrod at the pedal adjusted correctly. 2g cars are notorious for pedal pump-up ".

Go down to the lower section of this page and read. (http://www.roadraceengineering.com/clutchandflywheeltech.htm)

[volcomamskater]

Thanks guy's for the help, I'll get one of those steel braided lines ordered up, thanks Jakey. But with the push rod, can anyone know what the proper spec is? I mean since some people have a CFDF clutch, I have a ACT, wouldn't it be different on different systyems? When I had my slave and master installed, the guy put the push rod way to far into the master so it was holding the system partially open, I moved it back and it seems ok, but I;m sure now I will have to adjust my pedal travel. And hope that fixes it. Thanks again for the help.

[Jakey]

steel braided lines
https://secure.buschurracing.com/catalog/product_info.php?cPath=23_55&products_id=391&osCsid=87781fb19046cfbb40b703ad3cb4b417

http://www.roadraceengineering.com/ecldrivetrain.htm

[s1ngletracker]

hang on guys, he should check for crankwalk first. I had signs of pedal pump up, and my car was crankwalked like 0.60.