Jump to content
The mkiv Supra Owners Club

My clutch needs your advice!


neo2810

Recommended Posts

In order to begin this tale of woe, I must take you back to a sunny day in September. I know that my claim of sunshine in September in the UK in itself is ludicrous, but I assure you, sunshine there was, and a trip to the beach was planned. I had some business to attend to in North Shields, so a plan to meet family on the beach later was formed, and off I trundled. Business concluded, I nipped to the Silverlink Retail Park to purchase a game, for the nights entertainment. As I drove through of the car park, I experienced a lurch in first gear and my clutch pedal hit the floor. Knocking the Sup into neutral so that I didn't become one with the Micra stopped ahead of me, I managed to get my foot under the pedal and pull it back into place. From there, I nursed the car home with a combination of pedal pumping and foot hooking.

 

Jurgen took my sickly Sup into his care, and replaced the clutch master cylinder seals which were split as well as fitting a new, uprated clutch plate since the stock one was slipping. Job done, we thought, but oh noooo. I drove carefully for 100miles, bedding in the new clutch before giving it a little more welly to test things (not too much, just a little more to help with the bedding process). The clutch pedal hit the floor again.

 

Back to Jurgen's, and this time we replaced the seals on the slave cylinder. Picked the car up yesterday and everything seemed hunky dory for a while. I drove into work ok this morning, but popping out for a quick run an hour ago and once again, the pedal hit the floor. Basically when I pull off in first, the biting point is almost immediate and violent and the pedal doesn't release. I can pull it up with my foot with pressure (at the moment) and then 2nd, 3rd, 4th and 5th seem to work ok. As last time, if I ignore it, it will likely get worse to the point where I can't pull off in first at all (no pressure).

 

It's going back on Saturday where they will bleed it again just to see if it's just air trapped but they will also check the lines (in case there's a hole/split somewhere), and check another seal on the bulkhead. Does anyone have a similar experience of this type of problem, or educated ideas on other issues we may not have thought about?

Edited by neo2810 (see edit history)
Link to comment
Share on other sites

Get it on a ramp and observe the release bearing movement through the access covers in the bellhousing. I think Jamie had the release bearing carrier seizing on the input shft tube. If it's not that I would suspect the tiny fluid bleed hole in the clutch master cylinder is blocked or blocking with dirt.

 

Thanks Chris. I think Jurgen flushed both cylinders when fitting the seal kits so doubt it's a blocked hole but I'll ask him to check anyway. I'd have thought issues with the release bearing or the pressure plate teeth would have the opposite effect (ie: engaging the clutch even when pedal released)?

Edit: Re-reading your post, I see what you mean. If the release bearing carrier is partially seized and catching on the input rod, that could be sticking the pedal. Although I'd expect less resistance to pulling it back in place if it were just that. I'd expect the pedal to snap back up once the blaockage is cleared where now I have to keep pressure all the way up as the pedal resists coming up easily. Once up, it's fine though.

 

The pedal sucking to the floor suggests an hydraulic issue so my immediate thought is the line between the 2 cylinders is corroded or either of the cylinders has a hole in, since the cylinder internals are all new.

Edited by neo2810 (see edit history)
Link to comment
Share on other sites

If it's not that I would suspect the tiny fluid bleed hole in the clutch master cylinder is blocked or blocking with dirt.

 

That was my initial thought when I bled it off with Tony.

 

Assuming its not the pivot / linkage from the pedal to the rod on the master cylinder? If the pin has fell out, it could be hit and miss if the rod slips down the back of the pedal?

 

Either way, I'm sure Jurgen can fix it.

Edited by ugp (see edit history)
Link to comment
Share on other sites

Just a little more info for anyone following this. Driving home last night, the problem only occurs on pull off (whether in first or second as I tested). I pull off and the bite is almost immediate and not smooth. The pedal releases about an inch but as I accelerate it starts drawing to the floor and I push it down the last half inch and change to second. I then have to hook my foot under it and pull it back into position where changing to 3rd, 4th and 5th are flawless, no problems. Towards the end of the journey I found that if I lift the revs a little more before disengaging on pull off, the clutch sometimes doesn't "stick" and although not perfect, does lift right back and allow normal operation.

 

One other thing to mention is that when stopped at a light, I held in the clutch in 1st rather than hitting into neutral and after about 10 seconds the car quietly stalled, as if the clutch had disengaged by itself and stalled the engine, despite my foot on the floor. Worn release bearing sounding more plausible?

Link to comment
Share on other sites

Just a quick update for anyone using this thread as reference in future.

 

Jurgen replaced the clutch master cylinder housing and reservoir and it seems to have sorted the issue. I've only driven home from Jurgens but it feels completely solid now. No clicking that I had before, no variable pressure, and the chattering I had from the new clutch plate (which I thought was just the bedding in process) has gone.

I had a look at the new seal kit (which had only 100 miles on it as we fitted it first first) from inside the old MC and it was shot. It's hard to see the inside housing of the master cylinder properly but it did look as though there was a little wall inconsistency so it's likely that the inside wall was damaging the seal as it pumped, and fluid was flooding the MC.

 

So, sometimes it pays to go the cheap route first, and sometimes it costs. In this case it cost me.

 

Cheers to Jurgen for excellent service once again, although I must be a large chunk of his profits this month :D

Edited by neo2810 (see edit history)
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.