View Full Version : Nightmare clutch drag poblem
Hi all. The problem is on my track/ touge car. SW 20 GTS rev3. It has an ORC clutch and celica alltrac 2nd to 4th gears.
After about 1500miles of driving the clutch began to drag after driving. It would be fine cold. But little driving and drag. Making it hard or impossible to downshift without blipping the throttle.
Then I bled the thing. No change. Then I adjusted the pedal. Did 600miles of track day - no problem.
Now 500miles later it is starting to act up again. When cold OK. Warm up and drag.
Can't spot leaks either.
Paul Woods
15-03-2012, 06:56
I think i know what this is, is the little slave cylinder heatshield missing from it? I've seen them boil the clutch fluid from the exhaust heat. If the shield is there i'd suggest changing your slave cylinder.
cdwood2010
15-03-2012, 07:34
Yep, the same issue as brake fade.
For some reason that I always found strange (why doesn't someone invent something better) brake fluid compresses when it gets hot. As the Dark Lord says, replace the heat shield if it's missing, or identify how heat is reaching the clutch line or cylinder.
My dad used to have an Austin princess, and those old barges had 4 pot callipers on the front. The disks were slightly scored (not by much) and it used to suffer from monster brake fade on a hill. Changed the disks, problem solved.
Chris.
cdwood2010
15-03-2012, 07:36
Ooh, also check both bolts are securing the slave to the gearbox, Pat had a funny clutch issue that turned out to be a sheared bolt!
:)
C.
So far, this heat-shield thing is the answer that my mind can say "Makes sense".
Will have a look over the weekend.
Thanks a lot guys. Will keep you posted. ^^
Not had time to jack the car. Took the day off yesterday to do so. But the garage was in such a state I had to tidy my tools away and washing the floor up with degreaser.
2086
But in the mean time, it got me thinking... If the problem is over-heating fluid. Can Dot 4 or 5.1 help?
I know Toyota officially don't approve dot 4 or 5.1. But not sure if there is any good reason for that.
Anyone used dot 4 or 5.1 for their clutch lines?
No luck. The heat shield is there. I have bled the clutch fluid with dot4. (around 300ml). Basically until fresh brake fluid was coming out of the clutch slave cylinder.
I did it with one of those one way pipes. So not sure how good was it.
But for 2hrs the car drove perfectly. After going to the touge, the gears started sticking again.
One of the clutch lines is very close to the turbo oil pipe. This pipe is covered in Blitz Silicon hose.
Not sure if this is the problem. Thing is, last time I adjusted the clutch pedal, the car was fine for a few track days.
So I do not know how it could be a problem of pipe layouts...
I am thinking of changing the slave cylinder now, but it looks like a bitch to access. Engine mount from underneath and turbo from above... :S
Any advice on how to proceed?
Paul Woods
02-04-2012, 07:26
I think you're at the stage of having to investigate further, have you peeled the slave cylinder rubber boot back and checked for fluid behind it?
If there is fluid there you need to fit a new slave.
Ok, tonight is peel rubber boot.
Tommytank
02-04-2012, 18:18
I have one. Every few hundred miles I have to top up my clutch fluid, yet there is not a single drop leaking from anywhere? Phantom evaporating fluid?
Paul Woods
02-04-2012, 21:00
Ok, tonight is peel rubber boot.
Ok, but what about the slave cylinder issue? :laugh2:
I could not visually see the part with the rubber boot. I am really confused at how can it be so well hidden away.
Making me even more pissed of to think it might have to be an engine out job to replace...
Can anyone post a pic of its location on a tubby please?
Maybe I have found the problem. For some reason my slave cylinder is blue in colour.
http://www.tcbparts.co.uk/gearbox_clutch.htm
From this page, there is a blue clutch slave cylinder listed as for AW11.
I wonder why is this fitted. I want to swap it to the proper SW20 one.
This is probably why there is no heat shield.
But it also means that the clutch lines might have been replaced.
And... I wonder if th previous owner swapped it due to interference problems with the turbo oil/coolant feed pipes...
AAAARGGGGGGGGG (Stress)
Had a look at the AW11 manual (I should be able to remember really as I had one once...) and it looks like it would be impossible to swap over.
So I now have a new question, why is my slave cylinder blue.
Anyway, looks like removing the engine mount is going to have to be the first point of call.
Might as well pop over to Toyota and order my new slave + heat insulator bracket...
Paul Woods
03-04-2012, 07:20
Some real nerdy info here, the Mk1 slave has a slighly smaller bore than a Mk2 slave, now if you displace a full stroke of fluid from the master cylinder it will move a stock Mk2 slave cylinder (which is 7/8ths bore) around 13mm of travel at the rod end, around 2/3rds of that is actual throw at the release bearing due to the location of the pivot ball on the release fork (law of the lever etc) so roughly 9mm of actual bearing movement occurs at the pressure plate, not a lot is it!
With higher spec clutches you may start to lose some of this throw due to the heavy nature of the springs, a few vital mil may be lost as the bearing takes up the spring tension rather than start to release immediately.
If someone was to change the slave cylinder bore (by fitting a Mk1 slave for example), which is 13/16ths bore (Mk2 being 14/16ths for comparison) and you move the same master cylinders worth of fluid to that slave, by the laws of displacement it will throw further. It has been known for people to change the slave for smaller bore ones to get more throw with heavier clutches even with the pedal bite point adjuster screwed out to max.
That possibly answers your question as to why your slave is different. Slightly puzzled because in post #7 you said the heatshield was there? If the shield is missing that is definately your issue as first diagnosed and you can ignore all of my geeky crap in this post.
Paul Woods
03-04-2012, 07:21
Just to add, you can wrap some aluminium foil over it jus for testing purposes without going to all the trouble of removing, see if that temporarily fixes it.
cdwood2010
03-04-2012, 07:23
You're like a walking WSM.
:)
Paul Woods
03-04-2012, 07:27
What's a WSM? :)
snowtigger
03-04-2012, 10:01
Wood sport manual?
Women's sporty mankini
Paul Woods
03-04-2012, 10:58
Well sausaged male :)
cdwood2010
03-04-2012, 11:15
Widely Suspected Mincer.
:)
Tommytank
03-04-2012, 12:07
Worryingly saggy moobs?
peterguk
03-04-2012, 13:54
Well sausaged male :)
Not you then Paul..
An inch i think you said when we were discussing a very similar problem :icon_mrgreen:
Tommytank
03-04-2012, 14:42
Inch tall blue veined diamond cutter.
Actually I did some aluminium foil on Saturday night. It felt ok for a while, but is now back to shit. I want to check if the foil is still there as it was a nightmare to fit due to the tight space. Today I will try jack the car higher to have better access.
But even with foil, I cannot judge if the foil is doing good enough a job.
What about the rubber boot? Can I access it without taking apart the mount?
Tommytank
03-04-2012, 15:51
It should be accessable from the top of the engine bay. Might have to lean over quite a bit, and shuffle past some coolant hoses, but its there somewhere...
I feel so stupid, but got to ask some basic questions cause it is driving me insane...
2089
Based on the picture, bolt location 1 is where the bracket should be secured?
If so, problem 1 is missing heat shield.
Based on the picture, bolt location 2 is what kind of bolt?
I can see a bolt holding it where the face is machined, but when I feel around blindly, it is as if the head of the 2nd bolt is sheared off.
Going to try get my webcam in there to see....
Confirmed:
2 Bolts are ok (the ones that hold the slave) was simply feeling up the wrong hole :P
and heat shield is missing I guess (please heck this photo to confirm):
2090
I finally accessed the boot from under the car, but could not pull it back.
What's the process?
Tomorrow I will go order my heat shield and if needed order slave repair kit or new slave.
Thanks in advance.
Ehhhhhh....... got to stop posting so frequently. Removed the boot, the thing is bone dry, with no brown corrosion on the inside. Just non-shiny metal.
The new part of the puzzle is, how to put the boot back on with such little space.
Might have to drive the car as is to my mate's car lift... :(
Thought I still wonder, why did the car never suffer from these issues 4 months ago? Was the weather that much colder and my driving style that much less aggressive?! :/
Was going through Toyodiy and...
http://www.toyodiy.com/parts/p_J_1993_TOYOTA_MR2_SW20-ACMZZ_3105.html
Does anyone know why some parts have 2 listings? GT and 5F?
(What is interesting to me is that there is only 1 heat shield in spite of 2 slave assy part numbers with a different price).
AISIN's headquarters ironically is only a few metres from where I work lol! But I cannot just walk in and go "Hey?! What's the big deal guys?!"
I googled the 2 part numbers:
http://www.gkoautoparts.com/Products_indexshow.asp?lang=CN&SortID=194&ID=1795
http://www.gkoautoparts.com/Products_indexshow.asp?lang=CN&SortID=194&ID=1631
Seems like 1 of them is blue! Lol.
Paul Woods
03-04-2012, 19:07
Not you then Paul..
An inch i think you said when we were discussing a very similar problem :icon_mrgreen:
Shhh! get back to your speedo drive you.
Is there a trick to this damn rubber boot?
Paul Woods
04-04-2012, 06:51
Use a 90* pick tool or screwdriver to ease it back over the slave.
No screw driver access space. Will have to figure out what a bent screw driver thingy is called in Japanese when I go to buy one. :p
snowtigger
04-04-2012, 10:42
Looks like an L shape or a strong bit of bent wire can do it.
So, got the new heat shield today and just as I feared.... it does not fit. Not enough space. Hits the compressor housing :(
So, I used a thin sheet of aluminium, drilled 2 holes, and bent it around the pipes.
Now the remaining bitch is the damn rubber boot, I think I need a 2nd person to press on the clutch to do it.
Where? Who :/
Then put back the engine mount (that should be fun too...)
I hope so, but my confidence is low, because the original bracket is very tick gauge steel/alu. I am using 0.3mm gauge alu. And the space/distance from the heat sources are shorter (turbo oil lines and compressor).
But still, 3 hrs later, still struggling to get the rubber boot on.
The clutch lines and bleed bracket thingy cover the rubber boot.
I use all sorts of tools, 90degree pick, 70 degree pick, 70 degree tweezers... I want to bang my head till I bleed.
Might remove everything....
Amazing, this morning, 15min and the rubber boot was on (with the help of a squirt of silicon spray).
Everything re-assembled. Soon time to test. I am suspecting I need to re-adjust the clutch pedal though.
As I had set it to cope with the heating clutch fluid (if that was the root cause).
Long story short. I emptied all the clutch fluid cause I saw some black residue at the bottom of the master thank.
Now I cannot bleed the thing. Pumping is useless. I tried sucking from the nipple with a small syringe but I think it is too small.
What is the correct way and the hack way
cdwood2010
13-04-2012, 00:51
Lol, a few of us have been here before!
Ideally two or even three people for best results.
One person on reservoir watch / top up
One person on the pedal
One person under the car bleeding it!
usual way - open bleed nippy, pedal down, lock nippy, pedal up.
But do this with the slave pushed as far in as poss. It sounds a bit of a fiddle but works very well.
C.
How can you get a hand in there to keep the piston pushed in?
Ehhhhhhh....... can I suck the fluid out from the bleed instead?
I am hoping if I create enough vacuum, that it will be ok.
cdwood2010
13-04-2012, 07:37
Lol!
I use a big 'bodger' screwdriver, works very well.
You can bleed the system using pressure, have a search on here, there's a few ways to do it.
Make a pressure cap for the master cylinder and that will force fluid through. You can even bleed the system backwards!
C.
aussiemr2
13-04-2012, 09:30
I successfully bled my completely empty system by connecting a syringe to the bleed nipple and drawing through, hasnt missed a beat ever since
Just use a big syringe to get good pressure, I was not looking forward to the clutch bleed but it was a walk in the park :-)
All my garage work is done solo, so I just bought a vacuum bleeding kit for brakes/clutch etc. My one came from frost.co.uk and looks like a good bit of kit, I haven't got as far as actually using it though! I think vacuum bleeding is meant to be quicker/easier/more effective than pumping away at the pedal?
Ok guys, so I finally got somewhere.
Basically, syringe did not work, and I am not in a country where I can buy these bleed kits.
A friend pressed on the pedel. As he is stroking the pedal down, I opened the valve, and as soon as he hit the floor board, I closed the valve.
And repeat.
Finally, fluid with large gaps of air came out, and later portions of fluid with many micro-boubles, and finally just clear fluid.
Test drive - NG (not good), cannot change gear.
So, I adjusted the pedal as follows:
Pedal height - max
Rod length - max
Result:
Clutch disengages at about 10mm from the floor board.
Even after hard driving round the touge, stopping to let it soak heat, etc. The clutch was still disengaging.
I could still hear a rattling noise when the pedal is on the floor, which was the noise I heard when I got the car, and the noise my previous cars used to make with racing clutches in them (never understood why is that though).
But! New problem. When off the clutch (pedal fully raised). There is a rattling sound. It sounds to me like either the fork is rattling, OR it is the tapping sound between the fork and the slave piston.
If I press on the clutch pedal about 10 to 15mm that rattling sound goes out (the pedal is relatively soft in this range too). I tried 2 or 3 aggressive starts, and no problem, zero clutch slip.
So should I start tuning pedal position and rod length, or is there still some underlying problem?
I have a new slave cylinder, which I am ready to put, but would rather not to unless I have to, because it is a bitch to do and find someone competent enough to help me bleed it.
(My mate from the UK is here who has a modifying AE86 back home, so we both speak the same language, but local people here, don't even speak English...)
cdwood2010
16-04-2012, 07:31
Hi!
Clutch should disengage a lot sooner than 10mm from the floor! My guess is that you haven't got all the air out. Seriously, try bleeding it as you have been but with a big screwdriver pushing the slave piston back in as far as you can. That seems to be where a tiny bit of air gets trapped, and doing it this way avoids that happening (it did for me).
The rattling noise may just be slack that you've created between the slave and the clutch arm. I don't think you should have needed to adjust the pedal travel, unless you're using mismatched bits (can't remember your setup).
If you take your foot of the clutch and it rattles, that might be your thrust bearing. Or no oil in the gearbox?
Also, check (if you can) that the clutch arm is in the correct position, and that it is pivoting correctly. You might need to remove the rubber dust cover and get a mirror / camera in there.
Hth
C.
Thanks for the fast reply.
Regarding the pushing the piston back. I can't find anywhere to lean the screw driver against.
I will ask my friend to somehow assist me to do this again.
Regarding the rattling, I think it is rattling between the slave piston and arm.
I will check if there is air, but isn't the piston and arm always in tension, because the piston is pushed back by the fork's / pressure place force right?
To clarify regarding the rattling:
0% being pedal full up, 100% pedal full down
0 to 3% rattling (sounds like coming from slave/fork area) recent issue after trying to bleed and adjusting the pedal
5 to 90% just relatively stiff pedal
90 to 100% clutch disengaged with rattling sound (the type I am used to hearing from racing clutches, I read Ogura clutches also do this noise, if you think this is a trust bearing let me know, or if anyone has experience of such noise let me know too).
Regarding inspecting the arm... *sighs*
The clutch pedal had been adjusted several times by several people, so where it was before, was not necessarily right.
But right now it is definitely out of spec, as I started from this position to start from a working position.
Might have misquoted which clutch I have. I am running OS Giken. (Don't know which type, but there's also a lightened flywheel on there).
From description it sounds like the chatter from a tripple plate clutch.. also the rattling noise u get, could be release bearing or even a gearbox problem, I had a similar sound on an old car, would go away when u pushed the clutch pedal in but come back when car was idling in neutral.. I changed the clutch including release bearing and it was still there.. turns out it was the gearbox in my case..
aussiemr2
16-04-2012, 09:57
The sound you get with clutch to the floor sounds like the problem I had
I had set up too much pedal travel and the slave piston was pushing the fork too far into the clutch fingers causing them i think to touch the clutch disc
solution was to adjust for less pedal travel
If I set less pedal travel, I can't change gear.
Regarding the gearbox, it has been recently rebuilt (as it has gears from other transmissions).
Hmmmm... I will have a go at playing around with the pedal. To be honest, I heard this type of noise on full clutch stroke many times before (on other cars), and never thought of it as a problem.
Also, I would think that since the clutch is relatively new, the trust bearing would have been changed. (I cannot confirm cause I was not the owner at the time).
I think I will soon say to hell with it and take the box off.
Tonight I will check the mission oil level too (it should be ok, cause I replaced it myself, but after changing drive-shaft I had re-filled it again).
I also have a 1.5way LSD if that makes any difference to this analysis.
I am on the verge of smashing this car into the wall.
Everything looks normal, no leaks, I bleed every week and only clutch fluid comes out.
I even stuck a socket between the fork and housing so that when I press on the clutch the piston cannot open up while bleeding.
Nothing, just fluid came out.
But the pedal has too much soft travel at the top (too much free-play).
I can only make the clutch disengage properly with sill pedal settings.
I.e. clutch pedal rod, full extended into the master cylnder, and pedal height out of spec.
I have a new slave cylinder, but I doubt it is the slave, because I cannot spot any leaks.
What about the master, is it possible for it to fail without a leak? (Slosh fluid internally?)
cdwood2010
23-04-2012, 03:59
Spooky.
It has to be worth swapping things out just so that you can rule them out.
Starting with the master cylinder.
C.
Well, I already have a new slave, so I can swap that, as for the master, I was thinking of buying a seal kit.
Visually on the outside it looks like new. But when I changed the fluid last time, there was black/grey grains at its bottom.
Not sure if it was just dirt, the float deteriorated, or the seals perishing.
From description it sounds like the chatter from a tripple plate clutch.. also the rattling noise u get, could be release bearing or even a gearbox problem, I had a similar sound on an old car, would go away when u pushed the clutch pedal in but come back when car was idling in neutral.. I changed the clutch including release bearing and it was still there.. turns out it was the gearbox in my case..
Did you find out what was wrong the with gearbox? Mine was recently re-built... :/
So, some updates, the rattling noise with the clutch pedal on the floor is normal. I asked a few of my mates to confirm.
Then I gave OS Giken a call, and they confirmed that it is their design. If they don't rattle, there is something wrong.
Regarding the tapping noise with foot off the pedal.
MIGHT be the heatshield I made out of sheet metal, the metal is bent around such away that it overlaps, the overlap region might be vibrating and tapping.
Not too sure why it goes away when I partially press the clutch though.
But yesterday it was the opposite way, not making any noise with the pedal at the topic, but making the noise with the pedal have way through.
Now all is left to figure out is why I can't get enough travel without setting the pedal height too high and setting the rod fully extended.
By the way, can someone send me a photo of from where to where is the pedal travel measured? (I read the Toyota workshop manual). I don't have any carpets or friction pads on the floor as the manual says, so I am a bit lost. I want to confirm I am measuring the correct location.
Just a recent update. My clutch played up at my last track day, so I took the damn slave out.
It might be the part at fault. It seems to not return to the same position compared to the new one (the difference is only a couple of mm, maybe 5mm or so). :/
http://www.twobrutal.co.uk/forum/images/recovered/2012/05/93.jpg
cdwood2010
10-05-2012, 00:21
Interesting.
Are the cast numbers the same? Might be someone fitted a close match at some point.
C.
I am suspecting that is what happened. The numbers are different, but that could be because the existing one is a Toyota/AISIN, where as the new one is an AISIN name only (and came in a blue print box).
Paul Woods
10-05-2012, 06:52
That isn't causing your clutch drag, if you think about it, the old slave piston is further up the cylinder than the new one.
cdwood2010
10-05-2012, 07:22
That isn't causing your clutch drag, if you think about it, the old slave piston is further up the cylinder than the new one.
It might if it's the wrong part surely - different start and finish points on the travel?
C.
Paul Woods
10-05-2012, 07:29
In a word, no.
The only difference model to model is bore size, which gives an extra few mm of travel when engaging the clutch, neither slave should affect release.
They don't have different start and finish points and will both travel as far as the master cylinder dictates by fluid displacement.
The clutch pressure plate is so strong it will force the piston right back unless it was totally siezed, which it isn't, the only difference between that old and new slave is the old one has stuck a little towards the end of the bore, which means the light spring behind it can't quite push it to the end, but that has no effect on operation.
cdwood2010
10-05-2012, 08:29
Fair enough! I stand erected!
Just thinking out loud!
:)
Hmmm, having read what you said, I have to say, I only partially agree.
But we'll just wait and see, then I will explain the missing background. ;)
Paul Woods
10-05-2012, 17:58
Which bit do you not agree with?
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