Hello everyone,
I have been having quite the saga with my clutch master/slave cylinder and need some advice. I replaced my clutch a few weeks ago (with a Luk 05-065 kit) and replaced the clutch fork and master/slave assembly at the same time. I replaced everything as the symptoms I had were either indicative of a bad throw-out bearing and pilot bearing or a bad master/slave so I replaced everything. The clutch install went without issue, but the master/slave system has given me nothing but trouble. Now I am on my 2nd slave and 3rd master cylinder which just went bad again.
Attempt 1: I initially replaced the system with an FTE sealed/pre-bled master/slave assembly. That assembly had a leak somewhere that would reintroduce air into the slave but not leak out fluid. I bled the system 4 times over 5 days before giving up on it and pulling out the entire system to return it.
Attempt 2: Brand new Luk master cylinder and slave cylinder from Advance. For this I used the hose off of the original since it seemed to be in good shape and in the five years I've owned the jeep, it hasn't been a problem. The new parts were put in Saturday evening (6/7) and bled by filling the reservoir and pushing the slave in/out until bubbles stopped. By the following Thursday, it got swapped for Attempt #3. When being actuated, it was very squeaky and stiff and when I pulled it out, I could hardly push it in by hand.
Attempt 3: A different Luk master cylinder (from RockAuto this time) and reusing the Attempt 2 slave as it seems fine. The next day I drove 200 miles with it without major problems. By the end of the trip it was beginning to have some resistance but nothing terrible. After sitting a day, I then drove it 200 miles back home. By the end of that trip it was getting bad and now as of today is it is officially as bad as the Attempt #2 was before I swapped it, the same number of days later (~7 days). I was suspicious that maybe the Attempt #2 master wasn't fully bled or the internal seals went from being dry to being used in like 30 minutes so the seals were unhappy and died. So for Attempt #3 I filled the master and let it soak for ~1hr before installing it which doesn't seem to have made a difference.
Both Attempt 2 and 3 were very smooth without any resistance when freshly installed so I doubt the throw-out bearing sliding surface, clutch springs, input shaft splines or slave cylinder is causing issues.
To me this seems like Luk (or Luk's supplier) doesn't know how to spec seal material and about a week is how long it takes for the brake fluid to eat the seals. I used Prestone Dot 3 as per the reservoir cap, although maybe Prestone has some additive that these seals don't like? I hoped to avoid any production batch issues by buying from two different retailers.
Is there a better brand I should try? I went with FTE and Luk as they should be quality parts compared to some parts store or Amazon brand. Or do I just keep swapping them until I get lucky with a good one? Unfortunately the OE master has since sat out in the rain for 2 weeks so it probably wouldn't work to swap it back in.
I have been having quite the saga with my clutch master/slave cylinder and need some advice. I replaced my clutch a few weeks ago (with a Luk 05-065 kit) and replaced the clutch fork and master/slave assembly at the same time. I replaced everything as the symptoms I had were either indicative of a bad throw-out bearing and pilot bearing or a bad master/slave so I replaced everything. The clutch install went without issue, but the master/slave system has given me nothing but trouble. Now I am on my 2nd slave and 3rd master cylinder which just went bad again.
Attempt 1: I initially replaced the system with an FTE sealed/pre-bled master/slave assembly. That assembly had a leak somewhere that would reintroduce air into the slave but not leak out fluid. I bled the system 4 times over 5 days before giving up on it and pulling out the entire system to return it.
Attempt 2: Brand new Luk master cylinder and slave cylinder from Advance. For this I used the hose off of the original since it seemed to be in good shape and in the five years I've owned the jeep, it hasn't been a problem. The new parts were put in Saturday evening (6/7) and bled by filling the reservoir and pushing the slave in/out until bubbles stopped. By the following Thursday, it got swapped for Attempt #3. When being actuated, it was very squeaky and stiff and when I pulled it out, I could hardly push it in by hand.
Attempt 3: A different Luk master cylinder (from RockAuto this time) and reusing the Attempt 2 slave as it seems fine. The next day I drove 200 miles with it without major problems. By the end of the trip it was beginning to have some resistance but nothing terrible. After sitting a day, I then drove it 200 miles back home. By the end of that trip it was getting bad and now as of today is it is officially as bad as the Attempt #2 was before I swapped it, the same number of days later (~7 days). I was suspicious that maybe the Attempt #2 master wasn't fully bled or the internal seals went from being dry to being used in like 30 minutes so the seals were unhappy and died. So for Attempt #3 I filled the master and let it soak for ~1hr before installing it which doesn't seem to have made a difference.
Both Attempt 2 and 3 were very smooth without any resistance when freshly installed so I doubt the throw-out bearing sliding surface, clutch springs, input shaft splines or slave cylinder is causing issues.
To me this seems like Luk (or Luk's supplier) doesn't know how to spec seal material and about a week is how long it takes for the brake fluid to eat the seals. I used Prestone Dot 3 as per the reservoir cap, although maybe Prestone has some additive that these seals don't like? I hoped to avoid any production batch issues by buying from two different retailers.
Is there a better brand I should try? I went with FTE and Luk as they should be quality parts compared to some parts store or Amazon brand. Or do I just keep swapping them until I get lucky with a good one? Unfortunately the OE master has since sat out in the rain for 2 weeks so it probably wouldn't work to swap it back in.
