GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV

Clutch master cylinder upgrade ?

F

fuscobal

Go Kart Champion
Location
Romania
Hello guys,

As many of you know, our cars have problems shifting fast once the clutch is upgraded. I was seeking for a solution since the past 2 years and I've come to the conclusion that our OEM master cylinder is unable to push fast enough the pressure plate of an upgraded clutch. My clutch is a Sachs Racing SMF with organic disc. What I did until now to selve the problem was : replaced the entire clutch under warranty, installed the 42DD solid shifter bushings, adjusted the shifter cables several times, installed a shortshifter wich I also adjusted several times, installed the USP SS clutch line, removed the flow restrictor (situated inside the T piece just behind the slave cylinder > the same piece used for clutch aeration). All of these had no success so a few month ago I sent a mail to Southbend wich suggested the hydraulic system of the car might be weak and not able to push fast enough the pressure plate. What amazes me is there are tens of aftermarket clutches but no one thought of upgrading the master cylinder althoungh there are upgrades for other makes like Evos, Bmws, Corvettes...While browsing on the internet I've come across the Ap Racing range of competition master cylinders > http://www.apracing.com/info/index.asp?section=Master+Cylinders_2350 . Unfortunately, there are many types and many sizes for each type so I don't know if any of them would suit the mk5 Golf GTI and if it would cure the fast shifting problem. Any help would be appreciated !
 
abacuc

abacuc

New member
Location
Italy
fuscobal said:
Hello guys,

As many of you know, our cars have problems shifting fast once the clutch is upgraded. I was seeking for a solution since the past 2 years and I've come to the conclusion that our OEM master cylinder is unable to push fast enough the pressure plate of an upgraded clutch. My clutch is a Sachs Racing SMF with organic disc. What I did until now to selve the problem was : replaced the entire clutch under warranty, installed the 42DD solid shifter bushings, adjusted the shifter cables several times, installed a shortshifter wich I also adjusted several times, installed the USP SS clutch line, removed the flow restrictor (situated inside the T piece just behind the slave cylinder > the same piece used for clutch aeration). All of these had no success so a few month ago I sent a mail to Southbend wich suggested the hydraulic system of the car might be weak and not able to push fast enough the pressure plate. What amazes me is there are tens of aftermarket clutches but no one thought of upgrading the master cylinder althoungh there are upgrades for other makes like Evos, Bmws, Corvettes...While browsing on the internet I've come across the Ap Racing range of competition master cylinders > http://www.apracing.com/info/index.asp?section=Master+Cylinders_2350 . Unfortunately, there are many types and many sizes for each type so I don't know if any of them would suit the mk5 Golf GTI and if it would cure the fast shifting problem. Any help would be appreciated !
Click to expand...
Hi mate
On my Audi S3 (02Q gearbox) and Spec 2+ clutch SMFW I had the same problems, so I mounted a Girling 0.70 master cylinder (USP SS clutch line - Dieselgeek shortshifter - removed the flow restrictor behind the master cylinder), but since I achieved only few improvements, I switched back to the OEM master cylinder because I understood where was the matter and I finally fixed it.
The problem is due to the gearbox input shaft, which with the passage of time wear the gearbox (more tender than the steel shaft), and takes end float, so the imput shaft slides back and forth and the clutch can't disengage.
My mechanic has resurfaced the part of the gearbox where it houses the input shaft bearing, replaced the bearing and restored the correct coupling tolerances. Now the transmission is perfect.:thumbup:
 
F

fuscobal

Go Kart Champion
Location
Romania
Now you really caught my attention. I'm attaching some pics with my gearbox from 2 years ago, before installing the LSD. If you can please point me the input shaft it would be great !



Uploaded with ImageShack.us



Uploaded with ImageShack.us
 
F

fuscobal

Go Kart Champion
Location
Romania
Thanks abacuc. I suppose the circled area is the bearing + bearing housing then. Is that bearing what you replaced ? Also, what did your mechanic machine exactly ? The area underneath the visible part of the bearing or the circumference of the bearing ?



Uploaded with ImageShack.us
 
abacuc

abacuc

New member
Location
Italy
fuscobal said:
Thanks abacuc. I suppose the circled area is the bearing + bearing housing then. Is that bearing what you replaced ? Also, what did your mechanic machine exactly ? The area underneath the visible part of the bearing or the circumference of the bearing ?
Click to expand...

No it isn't; the gearbox input shaft has two bearings, you must consider that on the opposite side of the input shaft. My mechanic machined the bearing housing, then he put a shim to relocate correctly the bearing. Got it?
 
MMD

MMD

Oval Champion
Location
Qatar
abacuc said:
Hi mate
On my Audi S3 (02Q gearbox) and Spec 2+ clutch SMFW I had the same problems, so I mounted a Girling 0.70 master cylinder (USP SS clutch line - Dieselgeek shortshifter - removed the flow restrictor behind the master cylinder), but since I achieved only few improvements, I switched back to the OEM master cylinder because I understood where was the matter and I finally fixed it.
The problem is due to the gearbox input shaft, which with the passage of time wear the gearbox (more tender than the steel shaft), and takes end float, so the imput shaft slides back and forth and the clutch can't disengage.
My mechanic has resurfaced the part of the gearbox where it houses the input shaft bearing, replaced the bearing and restored the correct coupling tolerances. Now the transmission is perfect.:thumbup:
Click to expand...

I installed SPEC 3+ clutch , and my clutch isnot fully disengage, I came up with a conclusion that because the clutch is modified to handle high torque so the pressure plate apples alot high pressure on the slave cylinder which requires an uprated master cylinder to cope up with the new clutch and can apply more force on the pressure plate ....

PS: clutch has been bled .....
 
F

fuscobal

Go Kart Champion
Location
Romania
abacuc, finally got to take out the gearbox because of another probem I had with the engine on the track. The insput shaft, just as you said, is sliding back and forth about 3-4mm wich my mechanic says is way too much ! I didn't open up the gearbox yet but will do it these days and see what's the cause but I think it's exactly the same thing that you had !
 
abacuc

abacuc

New member
Location
Italy
fuscobal said:
abacuc, finally got to take out the gearbox because of another probem I had with the engine on the track. The insput shaft, just as you said, is sliding back and forth about 3-4mm wich my mechanic says is way too much ! I didn't open up the gearbox yet but will do it these days and see what's the cause but I think it's exactly the same thing that you had !
Click to expand...

I would bet on it...:rolleyes: I think VAG fixed this issue from 2009 with a new harder bearing housing.

Do not worry, the end of your trouble is near!:thumbsup:
 
F

fuscobal

Go Kart Champion
Location
Romania
Opened it and my mechanic said that a spacer needed to be where the bearing sat on the housing and perheps the guy that installed my Peloquin 3 years ago forgot to put it back !?!? I will make some pics next week !
 
F

fuscobal

Go Kart Champion
Location
Romania
You must log in or register to reply here.
Top