Rav 4 Clutch not disengaging

[SZ00]

Hi,

The machine is a 2003 Toyota Rav 4 2.0l AWD.

The car suddenly refused to shift into/out of any gears whilst driving on the motorway.

When stationary and engine off the car goes into gear (hence it is not a gearbox issue).

The clutch pedal feels hard (I bled the slave cylinder just in case but not air was trapped anyway)

I can start the car into gear with the clutch fully depressed and it doesn’t stall and I can take off normally but it struggles to change gear as it appears that the clutch doesn’t disengage fully.

The question is - is there any way of adjusting the slave cylinder stroke via the pedal travel? What should be the normal slave cylinder stroke to the fork be- maybe the cylinder isn't displacing enough somehow?

Also I noticed that there is no boot over the throw out bearing fork (or whatever it is called) so I was thinking that maybe some dirt has made it inside and it now dragging on the plate?

Any thoughts?  I really don’t want to start taking the thing apart if there is no need to do so….

Thanks!

 

 

 

[SZ00]

A quick feedback:

Just added a small nut between the slave cylinder rod and the fork and the clutch is now releasing almost fine (struggles slightly on the reverse but the car is driveable!!!).

Am I wrong to think that I should replace the slave cylinder? 

Thanks

 

[SZ00]

I need some help as I am stuck now- I replaced the slave and the master cylinder (second hand master cylinder), bled the system really well the,  clutch pedal now feels good but the clutch still wouldn't release! I measured about 15mm movement of the trust bearing lever (at the slave cylinder location) when the clutch pedal is fully pressed - is this enough or could the second hand master cylinder be bad or could something inside gone wrong?!? 

Please if anyone has any suggestions please shout :) 

many thanks,

jay 

[TomdeGuerre]

Hi James, sorry you’re having hassle with the clutch. Couple of possibilities spring to mind: 

See if there’s an accumulator in the hydraulic circuit between the master cylinder and the slave cylinder (this post discusses it http://www.toyotaownersclub.com/forums/topic/129169-rav4-just-lost-drive/ ). If so, does it appear OK, do you need to bleed it separately etc? 

Are you sure you mean 15mm travel for the release fork (item 31204) at the slave cylinder side. That does not seem anything like enough. The fork operates at a leverage ratio of about 4:1 so this would represent less than 4mm of actual travel at the other end. The fork might be bent, they can take a set after operating for many years, and this may be aggravated by wear on the pivot bolt (item 31236B). 

The clutch driven plate or friction plate (item 31250) may be seized or partially seized on its splines, especially if it has been operating with the rubber cover missing. This would mean that it might continue to drive the gearbox regardless of the clutch pedal operation. See if you can inspect it through the access hole, if you see any signs of corrosion try some penetrating oil on the splines but be very careful not to get any oil on the friction plate surface or you will knacker it. 

You might also want to look at this thread. http://www.toyotaownersclub.com/forums/topic/125298-rav-4-clutch-master-cylinder/

 

 

[SZ00]

Thanks very much Tom,

I don't have an accumulator.

Yes, I am sure that the fork moves only 15mm at the slave which seems to be my problem I believe. I was recently told (by someone that has the same machine and measured his movement) that this should move about an inch (25.4mm). I have  ordered a brand new MC just to eliminate the chance of the second hand unit to be faulty.

As for the bending of the fork - how is this related to the movement of the slave cylinder's rod?

It would appeat that the system isn't bled properly but here is what I did:

Initially I used a vacuum pump (specifically designed for bleeding such systems) connected to the slave. After a while (and no luck with the clutch disengaging) I switched to the old school method with a helper on the clutch pedal. My helper was pumping the clutch pedal couple of times and holding it presed while I was uncrewing the bleeding screw on the slave cylinder with a hose connected to it. I kept repeating this exercise for almost an hour and nearly a litre of brake fluid - absolutely no air bubbles were coming out so I thought that the system is bled?!? BUT still only 15mm of movement?!? 

I have also adjusted the master cylinder rod (on the clutch pedal) all the way out so that the MC has the longest possible stroke! 

Any ideas?

   

[TomdeGuerre]

Test the hydraulic circuit. Bleed the system the old fashioned way (open bleeder, press clutch pedal down right to the floor and hold down then close the bleeder. Now let the pedal up, wait a couple of seconds to let the master cylinder fully recuperate then repeat several times until clear fluid flows). Make sure the reservoir is topped up at all times. 

Take out the slave cylinder push rod and place a G clamp over the slave cylinder and tighten the G clamp so the slave cylinder piston cannot pop out. Now press the clutch pedal and make sure it feels solid. If you have any softness in the pedal look at the pedal pivot bushes, pins and associated linkages etc. Also check for any fluid leaks or swelling of flexible hoses.

If there’s nothing visible externally, and you still have softness in the pedal, the master cylinder seals might be leaking internally. The leakage would eventually be visible at the back of the m/cyl where the pedal push rod enters it. If so, your replacement master cylinder should cure that. 

Be sure the master and slave cylinder bore sizes are correct. A smaller bore master cylinder will give you a lighter pedal but less linear travel on the slave cylinder and vice versa. A larger bore slave cylinder will give you less travel and vice versa. 

Make sure there’s no extra mats or carpets on the floor restricting the clutch pedal travel. 

Try these first and see what happens. If you don’t get the hydraulics right there’s no point in checking anything further.

[SZ00]

I just tested the hydraulic system as you suggested above. I clamped the slave with a g-clamp and pressed the clutch pedal- it felt totally solid - no softness at all! I bled the system again and again - no air bubbles at all! No leakage anywhere, no play anywhere nor carpets under the pedal but it would still only displace 17mm (looked it it carefully this time) at the slave :( 

I really don't know what else to do??? Could it be something gone wrong inside the clutch housing so that it physically restricts the movement? Maybe a broken spring or something that got stuck in the pressure plate? 

Any other suggestions?

Thanks for the help so far! 

 

[TomdeGuerre]

So from what I can gather your clutch works OK if you put a small nut into the slave cylinder which suggests to me there's not much wrong with your clutch itself.

I assume the 17mm travel you're getting is with the system all connected up and when you depress the pedal and actually work the clutch. DO you know how much linear travel you can get with th slave cylinder push rod disconnected? If the best clutch slave cylinder travel is only 17mm and you know the norm is ~ 25mm then you need to look further outside before taking the gearbox out to look inside. 

Is the clutch pedal stop adjustment right back? because that will affect the travel, so make sure it’s backed off all the way out. Check the clutch pedal comes fully back with your foot off, don’t just trust the return spring, pull it back to make sure.At this stage don't worry about whether the clutch pedal looks higher than the brake pedal.

Check the adjustment of the push rod between the pedal and the master cylinder. On some cars it’s an eccentric cam adjustment for the push rod, on others it’s just a screw and locknut adjustment, check and see which yours is. The normal setting is to adjust the push rod so there’s a clearance between the pedal and the master cylinder piston. In cases like yours, where travel is minimal, you can adjust it further and take up all the play. Don’t extend it so far that the master cylinder is halfway down its stroke though otherwise you’re defeating the object. If you get any appreciable adjustment try the travel again. 

 

[SZ00]

That with the nut worked but for some reason after couple of shifts it went back to normal (it wouldn't disengage). 

I then replaced both the master and the slave cylinders (both of which are brand new now and for this car). Tonight i checked all of these things that you mentioned (most of which i already did):

 

1) The master cylinder's rod is adjusted all the way back (only hangs on 2-3 threads just to make sure that it is as far backwards as possible). 

 

2) no carpets at all now - i have pulled everything away just to make sure that nothing is restricting the pedal itself (100% all clear)

 

3) I checked the movement of the slave cylinder's piston when not attached to the fork and it is even less than 17mm when i press the clutch pedal once fully to the floor! How is this possible - i am confused?

 

Again, no leaks anywhere, the clutch pedal feels absolutely solid when i put the g-clamp over the slave!

 

I was bleeding for hours and two bottles of brake fluid - not a single air bubble was coming out! 

 

Here are some photos of the slave's displacement before and after the clutch pedal is fully pressed:

 

What am I doing wrong??? 

[Conrod]

On the clutch fork arm....I've seem the arm wear through the ball socket inside the housing due to it being dry  this would affect the ratio of movement , it's sounding like time to get the gearbox out for inspection.

      It's also  possible for several of the clutch pressure plate "fingers" to have broken or worn away ....again time for gearbox out for inspection .

[SZ00]

Thanks very much for the input Conrod.

I feared that this is probably where it is going (taking the gearbox out) :(

 

I can see how a worn ball socket would affect the ratio however why would this limit/restrict the linear movement at the slave?

 

Also worn or broken pressure plate fingers crossed my mind as well but again why and how would that affect the linear travel at the slave?

 

I was thinking that something (a finger or a spring) may have broken and got stuck so that it physically restricts the trust bearing movement however when I press the clutch pedal it goes all the way down and it doesn't feel like it hits a hard stop (like when i put the g-clamp over the slave cylinder).

 

So the above still makes me think that something is wrong with the hydraulics but I can't figure out what!?! 

 

Thanks again for the input guys - really appreciated it and I welcome any other advices you might have as I really don't want to drop the gearbox for nothing :( 

[Conrod]

When you added the nut and that increased the throw of the slave cylinder, you said it worked  briefly then when back to how it was ( if I read that right)... to my mind something is breaking or maybe bending in the mechanical linkage in the bell housing.....so it still sounds like time to get your spanners and axle stands out 😟

[SZ00]

That's a fair point Conrod :) In fairness I haven't tried putting a nut (or extending the slave's rod) after I installed the new cylinders (as I shouldn't have to really!).

I'll try that tonight just to see whether it will disengage - still even if something is bending inside I would expect the full linear travel from the slave cylinder to be unaffected. 

Is separating the gearbox on the RAV4 doable with the axle stands and couple of jacks to support it?

From what I read here and there I would have to drop the bottom subframe, remove the driveshafts, undo the clutch housing bolts and the lot (the gearbox and the transfer box should shift to the right sufficiently enough to inspect the clutch? Is this right?

Thanks :)  

[TomdeGuerre]

Hi James, the lack of linear travel is a problem I’d like to see you get the answer to before you go to all the trouble of taking out the gearbox.

You said you actually got less travel when you took out the push rod, only thing there I can suggest is between you removing the push rod and actually measuring the travel, the slave cylinder piston moved outwards a bit itself, under a slight head of fluid from the reservoir. So you might have measured only the residual travel unless you removed the push rod then pushed the piston all the way back in before you even started to check the travel. 

I wanted you to start adjusting out the push rod between the pedal and the master cylinder, it’s sometimes effective where operation of the system is marginal. People will tell you "Oh no, you’ll wind up burning out the clutch doing that because as the release bearing will be riding the pressure plate all the time and as the clutch wears the slave cylinder has to automatically adjust". But you can adjust the push rod a few turns to lengthen it so long as you leave the internal port clear between the reservoir and the fluid line then the slave cylinder fluid will still have a return path and no residual pressure can build up in the line. 

Don’t know about removing the gearbox on yours but you might want to take a look at this thread and its related ones.

http://www.toyotaownersclub.com/forums/topic/136334-replacing-5th-gear-on-41-and-42-gearboxes/

 

 

[SZ00]

This is what i did Tom with regards to adjusting the master cylinder's pushrod...

 

Anyway, here is the progress from tonight: 

 

This probably isn't the most elegant way of doing it but I inserted a 15mm piece of aluminium between the fork (cable tie to the fork) and the housing (see the photos below). This way I got an effective travel of 22mm and BINGO - the clutch disengaged just fine - i was able to select every gear with the engine running however the clutch was slipping quite badly and i had almost no drive!

 

Then I removed the aluminum insert whilst keeping the clutch down (so that the slave was still displacing about 22mm). I started the car (without fully releasing the clutch pedal) and I was able to select gears and drive forwards and backwards no problems at all - the clutch was releasing smoothly and everything seemed normal!!! 

 

After i finally released the clutch pedal and pumped it couple of times it become difficult disengage again and eventually impossible (after 5 minutes) to shift.

 

I thought right let's try the aluminium insert once again - put it back in - same thing - it displaced just over 20mm - clutch releasing just fine however this time I had drive there was a really bad judder when i released the clutch (seriously jerky!) :( 

 

Then I removed the insert - and although the clutch would still disengage and shift gears the nasty judder (when releasing the clutch) was still present?!? 

 

I went for a quick drive and although the clutch wasn't slipping it was very jerky on releasing! :( I also noticed that when I accelerated on a low gear and went up the RPM and then let go (the engine brake effect) there was some vibration that was coming from the front :(

 

After about an hour it will still shift (with only 17mm linear travel at the slave) - a bit hard but definitely disengaging - this wasn't possible yesterday with the same travel - i have no clue what on earth is going on! How certain are you about the 25mm linear travel norm?   

 

It would appear that something has gone wrong inside now because of that jerky clutch release??? :(  I sprayed some WD40 inside the housing as the whole bit seemed abit rusty as the boot was missing... Could have I contaminated the disk? 

 

What do you think guys??? 

[TomdeGuerre]

  

One thing I don’t get, James, is on your first photo you show that you put the spacer in between the slave cylinder body and the clutch fork. I would have put a different type of spacer in between the push rod and the clutch fork but probably no matter. Just to clarify the 25mm travel: it was you who first quoted 25mm saying … “I was recently told (by someone that has the same machine and measured his movement) that this should move about an inch (25.4mm)”…  

Seems to me it’s gearbox out time now for further investigation. Far as I can make out there’s no modified parts available for master or slave cylinder or any TSB’s for cracked bulkheads, pedals or the like The judder you’re now getting is quite possibly due to WD40 contamination but in any case you’re probably better getting a full clutch kit. You can buy an LUK kit from some motor factors or Parts King on here can supply a genuine Toyota kit at members discount. 

There’s quite a number of threads about crunchy gear changes on the RAV 4, with the correct gearbox oil being an important issue. Also  in this thread there’s a post about the gear change cable lubrication you might want to read: http://www.toyotaownersclub.com/forums/topic/118384-bad-gear-selection/#comment-1065038  also see this one http://www.toyotaownersclub.com/forums/topic/105548-moved-vague-clutch-on-rav4-2006-20l-petrol/#comment-957593

I know these are nothing to do with the lack of linear travel but they’re worth bearing in mind. As far as taking the box out with the car on axle stands the general consensus is no chance, there’s just not enough room and it’s too heavy and awkward. Can you get the use of a ramp or pit somewhere otherwise I’d recommend an independent garage somewhere. Burst knuckles, a twisted back and shoulder injuries tend to take all the fun out of it! To be clear I’ve never done the RAV 4 box but I’ve done plenty of others including heavy commercial trucks. So best of luck with it, I’d certainly be interested to know the outcome.

  

[Conrod]

All jokes aside ....Haynes do a repair manual for the RAV4 could prove to be a help with the gearbox removel ... Manual number 4750 👍🏻

   

[TomdeGuerre]

Came across this PDF about RAV 4 clutch, has some interesting data.

 

RAV4 Clutch.pdf

[SZ00]

Thanks for the help guys! I'll attempt to replace the clutch myself next week... I'll have an access to an engine lift and a gearbox trolley however the the car will still be on the ground though (probably jacked up and supported well obviously). I just can't justify giving £700 to a garage just for the labour. If I messed it up then that may be the only way to get the car fixed but I'll try to do it before this... :)

[TomdeGuerre]

Meant to copy this one:

 

[SZ00]

Guys, I need more HELP!

 I attempted to change the clutch and I got everything out (subframe, starter, cables, etc) but I got stuck on separating the gearbox (with the transfer box) from the engine! 

 

Before you ask I am 100% sure that I have removed all 10 bolts and I have even managed to separate the gearbox about 5mm away from the engine with the use of couple screwdrivers that I gently hammered at various places around the housing. However the damn thing wouldn't separate any more!!! As soon as I take the screwdrivers out the cases close almost completely. I have supported the engine and the gearbox underneath with different jacks as well as I have additionally supported the gearbox by an engine hoist from the top. I initially put just a little force on the gearbox from underneath (just so that it supports its own weight) then when it didn't come out I tried another 1000000 combinations trying to free up the gearbox but no luck at all- it wouldn't separate more than about 5mm. I feel that I start bending the case (locally) if I pry (using pry bars) too much. 

 

Also when I separated it slightly this thing (see photos) came out - it looks like that this is part of the trust bearing as when I put it over the new one it matches the diameter perfectly! So assume that it is a mess inside!

 

I have a bad feeling that another piece of metal like this might got stuck on the shaft which in turn makes it !Removed! hard to separate!

 

Any suggestions??? I have been hammering, shaking , pulling and swearing for about 6 hours today and no luck :( 

[Conrod]

Are you getting 5 mm gap all the way around the bell housing or is it staying tight at the top close to the engine ? There a two locating dowels each side and they can rust and corrode stopping it coming apart.

     

[TomdeGuerre]

Good call from Conrod about the dowels. If not the dowels possibly the primary shaft seized/sticking on the splines of the clutch driven plate. If so, put loads of best penetrating oil you can get on the splines through the access hole in the bell housing and let it soak for a while. Maybe drive in a few small wedges equally around bell housing and leave overnight to see if the constant pressure will persuade it to let go.

If that doesn't work can you cut away a small part of the bell housing to give you access to the bolts which hold the pressure plate onto the DMF? Remove one bolt at a time, rotating the engine to get sequential access. Other thing (unlikely) would be the spigot end of the primary shaft stuck in the flywheel bearing, that would be a pig.

[TomdeGuerre]

2 minutes ago, TomdeGuerre said:

Good call from Conrod about the dowels. If not the dowels possibly the primary shaft seized/sticking on the splines of the clutch driven plate. If so, put loads of best penetrating oil you can get on the splines through the access hole in the bell housing and let it soak for a while. Maybe drive in a few small wedges equally around bell housing and leave overnight to see if the constant pressure will persuade it to let go.

If that doesn't work can you cut away a small part of the bell housing to give you access to the bolts which hold the pressure plate onto the DMF? Remove one bolt at a time, rotating the engine to get sequential access. If you managed to remove the bolts it would allow separation even if the release bearing has broken up and is catching on the diaphragm fingers of the driven plate.

Other thing (unlikely) would be the spigot end of the primary shaft stuck in the flywheel bearing, that would be a pig.

 

[SZ00]

Thanks for he rapid responses as  usual! 

The gap is slightly bigger on the front side of the car but i don't jave access on the rear (as the space is "blocked" by the transfer box. I tried to stick a screwdriver from the bottom along the rear side of the housing but I managed to crack the engine housing slightly (not big deal as it is just a small part that covers the flywheel) but I don't want to /afraid to stress that area anymore!

I sprayed nearly a full can of WD40 inside the clutch housing targeting the shaft! Didn't seem to help :(

The dowes was the first thing I thought of BUT believe it or not it doesn't seem to have any- when I split the housings slightly I ran a small ruler along the edges trying to see where the dowes were so that I could spray that area more but the ruler ran free around the full circumference?!?

Tom, are you suggesting to make holes in the housing to undo the pressure plate? Isn't this abit extreme :) 

That's a good call to leave it with all the screwdrivers in - didn't think of this!

Any other suggestions?