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-   -   S4s clutch adjustment (https://www.lotustalk.com/forums/f164/s4s-clutch-adjustment-321074/)

Seraph 08-14-2015 03:29 PM

S4s clutch adjustment
 
2 Attachment(s)
How should I adjust my clutch in consideration of the following details?

ISSUE: When pushing clutch down, it isn't fully disengaging.
DETAILS: I replaced the clutch and when I test drove it, the gears ground when trying to go into reverse every time. The clutch was engaging near the floor instead of towards the middle. The clutch would be fully engaged in 1st and reverse after lifting the clutch only 30-40mm (2"). I also noticed my clutch pedal is missing the down stop screw. Without the down stop, I have measured about 178mm of travel and the service manual says 175 - 180mm is normal (See 1st image below).

I don't want to adjust the Threaded Abutment screw too much because I'm currently at 11.4mm (spec = 9mm-12mm). You can read in the 2nd image why not to go outside that range.

Where should I make adjustments to resolve this issue?

Vulcan Grey 08-14-2015 03:37 PM

Are you going into 1st or 2nd before going into reverse? You do have to do that.

How is the clutch feel? still soft or hard?

Seraph 08-14-2015 03:47 PM

I just checked it again. The clutch feels a tad soft from top to 1/3 of the way down when pushing the pedal, but I might be imagining that. I checked and made sure clutch master was full of fluid. Going into reverse from 1st or 2nd doesn't matter; I still get grinding noise as it slips fully into gear. Going into 1st requires maybe less than 1" from floor before the gear starts engaging.

delomike1049 08-14-2015 03:52 PM

I had issues with my car because the cylinder wasn't hooked up to the correct hole on the pedal. Make sure yours is hooked up to the hole marked 'C'.

Seraph 08-14-2015 03:58 PM

I did read this procedure on a V8 clutch (read the very last post). Not sure if it is the same for mine, but I would be guessing so...

I also read "A newly installed clutch will have a take-up point closer to the floor.
If the clutch engages instantly when the pedal is released from the fully depressed position, then this should be investigated." on this website. I have bled the clutch slave and there shouldn't be any worn parts, since it was operating fine before I replaced the clutch.

Seraph 08-14-2015 04:01 PM

Quote:

Originally Posted by delomike1049 (Post 4289234)
I had issues with my car because the cylinder wasn't hooked up to the correct hole on the pedal. Make sure yours is hooked up to the hole marked 'C'.

I'll check that, but I didn't mess with the clutch master, only the clutch slave. Also, the clutch pedal was working fine before I replaced the clutch that was slipping in 4th gear.

Thanks.

carbuff 08-14-2015 04:19 PM

Quote:

Originally Posted by Seraph (Post 4289250)
I'll check that, but I didn't mess with the clutch master, only the clutch slave. Also, the clutch pedal was working fine before I replaced the clutch that was slipping in 4th gear.

Thanks.

Jim, Don't worry...the SIR pedal box arms don't have the [C]lutch and [B]rake holes IIRC.

Seraph 08-14-2015 04:21 PM

1 Attachment(s)
I assumed the Lotus position to look at the clutch pedal. It doesn't appear to have any more room/threads on the clutch master cylinder push rod to extend the pedal upward. I think that's the direction I need to go...

Seraph 08-14-2015 04:26 PM

Quote:

Originally Posted by carbuff (Post 4289298)
Jim, Don't worry...the SIR pedal box arms don't have the [C]lutch and [B]rake holes IIRC.

Good. Because I used a mirror and looked all around... the only hole I could find was the [A] hole in the driver's seat!

sleekgt 08-14-2015 04:41 PM

Quote:

Originally Posted by Seraph (Post 4289330)
[snip]the only hole I could find was the [A] hole in the driver's seat!

Now THAT was funny! rotfl

carbuff 08-14-2015 04:43 PM

Quote:

Originally Posted by sleekgt (Post 4289370)
Now THAT was funny! rotfl


Yep! :D :D :D

jtrealty 08-14-2015 05:02 PM

If the pressure plate was not set up exactly right you will never be able to adjust it right by adjusting the pedal linkage. The dimensions of the pressure plate are also very important. Just a little too thin or too thick and it won't work either. If you got the clutch from one of the Lotus vendors you need to call them. If you had the flywheel ground and they didn't grind the step too, that may be the problem. Over-adjusting the pedal linkage may cause other problems so go carefully.
David Teitelbaum

lotus4s 08-14-2015 05:58 PM

I have run into this same problem several times in recent years replacing clutches on 4 cyl Esprits particularly on S4 and S4s models. Personally I think it has something to do with a difference in the pressure plates from the original OEM parts as David alluded to above.

Don't bother trying to change the adjustment at the pedal if you have the recommended travel as you don't want to put any pre-load on the master cylinder and you need to maintain that 2-5mm free play at the top of the stroke. That can cause other problems with it not fully releasing. And the S4s never had any downstop as shown in the manual.

The solution that I and others use who have been there many times, is to go ahead and increase the fork threaded abutment screw dimension to whatever is needed to get complete disengagement but no more. Adjust about 1/2 mm at a time and check. You also should be able to spin the pushrod fairly easy with your fingers. It shouldn't have so much pre-load on the clutch plate that you cannot spin it.

This is all assuming that you are sure that the rest of the system is in good working order and fully flushed and bled. If any air has gotten into the system, bleeding can be a real pig.

By the way, the actual threaded adjustment spec for the S4s is 12.5mm. If you go over that at all, it shouldn't be more than a millimeter or so.

Good luck!

Seraph 08-14-2015 08:19 PM

1 Attachment(s)
@jtrealty - I did have the pressure plate ground down. I noticed the step wasn't as prominent and Vulcan Grey measured with his caliper and it was wasn't within spec (05.mm-0.6mm). So I took it back and had them grind it to be within spec. The step wasn't as defined and sharp-edged, but it was still good (at least I think so). The clutch plate and pressure plate was from JAE, but not sure where they sourced it from exactly. Thanks for the words of caution. I was hoping to get input like this before I go all loose cannon on fixing this.

@lotus4s - Didn't know the missing downstop was standard on the S4s and the manual was telling me otherwise. The slave push rod spins freely, but if I put the car in 1st gear with the clutch all the way in, the wheels spin (while on jack stands). But if the car is resting on the ground, there isn't any forward motion with the clutch pushed in. Did I put something back together wrong?
The clutch was bled. Then I detached it and hung it upside down to get the bleeder nipple at the top and bleed it a little more. In order to get the push rod back in far enough for me to bolt the clutch slave back on, I had to crack open the line (not the bleeder) to relieve some pressure. Then I bled the slave again with a couple more foot depressions (using the bleeder nipple) and no bubbles.
Thanks for clarification on the abutment screw spec being up to 12.5mm for the S4s. I'll probably make some small adjustments to see if that fixes it and then possibly make some small adjustments at the clutch pedal.

Thanks for your feedback guys! :bow:

MidLifeZ 08-15-2015 05:18 AM

I went through the same thing a year or so ago. I did the initial clutch swap myself and afterward shifting went to )%*)$!

Having done a lot of clutch replacements in the past and even after going back through everything finally had to throw hands up in the air. Out of time to do on my own I took it to Sports Car World in Dallas. The brand new clutch had a manufacturing defect. Sent back to JAE and they swapped it out. I also had SCW adjust everything from front to back. My 1994 S4 shifts as good as any car I have ever had, like butter, now.

Seraph 08-15-2015 09:49 AM

I decided to check to see how much play there really was at the top of the pedal before changing any adjustment points. I had another person push the clutch slowly until I felt resistance while spinning the slave push rod. I had them stop when I could still rotate the push rod but definitely felt a significant amount of resistance. I measured about 20mm of clutch pedal travel which is way more than the 2 - 5mm specified in the manual. So I bled some more fluid through the clutch and still no bubbles or change in the clutch pedal.

Since the wheels spin while jacked up with the clutch pushed all the way in, I figure there's enough tension on the fork already. So it is probably best to adjust at the clutch pedal a little bit first (noob engineering logic being used here). However, I can't get the pin out (I did successfully remove the cotter/retaining pin though). I hammered with a little ball peen hammer (because there is no room to work under the dash) and it doesn't budge. So I think I'll go try to loosen one of the nuts and then try rotating the push rod instead since this bracket holding the 2nd nut can't be removed.


...only 6 days until LOG35 -eek- I might have to put the old clutch back in if I can't get this one to work @MidLifeZ .

Vulcan Grey 08-15-2015 10:30 AM

@Seraph Re-read what @lotus4s wrote.

The pedal adjustment is probably fine. The 2-5 mm of free play is totally free jiggle room, the piston is not engaged at all. No force required at all. it's not something you can feel with a foot. Gently grab the pedal and wiggle it up and back (not really down) that wiggle room is just to make sure the piston has returned all the way.

What Jim @lotus4s said was that you probably do need to adjust the fork. TO what he said (not what the book has). He knows the S4s.

Seraph 08-15-2015 12:25 PM

I learned that the easiest way to adjust at the pedal was to loosen the nut closest to the clutch master cylinder and then rotate the push rod using fat needle nose pliers. After adjusting the push rod towards the master (i.e., moving the clutch pedal upwards) about 4mm, I put the car back in the 1st with the clutch depressed. I noticed that the wheel spin was much slower than before which would imply that the clutch is disengaging more. @Vulcan Grey , looks like I have about 2mm of sloppy loose play at the top of the clutch throw.

I took it for a test drive and it feels like it is still engaging really close to the floor board. Also there isn't much pedal travel before it is fully engaged (feels like I'm popping the clutch into gear even though I'm not trying to). I only drove for about 5 min. and didn't notice any slipping and all gears seemed to shift fine. At this point, I believe it is driveable. Perhaps I need to give myself a little time to adjust to the new clutch feel.

The abutment screw was already at 11.5mm so there isn't much more room to change it to the max of 12.5mm. I'm going to adjust that next and hopefully that helps fix it all. After this, there isn't any more adjusting I can do since I'm at the limits.

On a side note... I changed the translator back around to factory defaults. Previous owner had moved the gearchange cables to the top of the translator in order to make it a shorter throw. But I didn't much care for how "tight" the shifter felt as a result. I then decided to see if I liked it better with the normal setup. The regular setup definitely glides a lot more smoothly between gears, but the throw is very long feeling. Probably a good thing for me since I was shifting too fast into 2nd gear and getting a slight grind.

Vulcan Grey 08-15-2015 12:52 PM

Quote:

Originally Posted by Seraph (Post 4290938)
I noticed that the wheel spin was much slower than before which would imply that the clutch is disengaging more. @Vulcan Grey , looks like I have about 2mm of sloppy loose play at the top of the clutch throw.

I took it for a test drive and it feels like it is still engaging really close to the floor board. Also there isn't much pedal travel before it is fully engaged (feels like I'm popping the clutch into gear even though I'm not trying to). I only drove for about 5 min. and didn't notice any slipping and all gears seemed to shift fine. At this point, I believe it is driveable. Perhaps I need to give myself a little time to adjust to the new clutch feel.

The abutment screw was already at 11.5mm so there isn't much more room to change it to the max of 12.5mm. I'm going to adjust that next and hopefully that helps fix it all. After this, there isn't any more adjusting I can do since I'm at the limits.


https://www.lotustalk.com/forums/atta...utch_slave.jpg

Look at how the geometry of the abutment screw is working with the slave. If you adjust the screw toward the slave, that effectively increases the stroke, meaning you'll be able to get the clutch to release more... Yours is not releasing far enough.

Adjust the screw to 12.5mm and see how that does. ignore the book, that is the safer side of the spec anyways it means that the clutch will start slipping earlier as it wears, but in your case it is not releasing enough, so it needs to be adjusted.

A single mm is a lot to a clutch. Don't forget you had your clutch ground anyways, so that needs to be adjusted in that direction anyways.

forget about the pedal... or at least set it back to 4-5mm of free play. 2mm is not enough.

Vulcan Grey 08-15-2015 12:57 PM

also. take a photo of your master and slave so we can see if they are the original ones or aftermarket ones. SOme of the after market ones might need a different rod length or adjustment.


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