Clutch fork problem

[Spode]

hey everyone, I got a RWD bigport 4age in a KE55 and have a big problem. Motor is running and everythiung is fine in that department but im having problems getting my clutch to disengage/engage properly. I have got the wrong clutch fork and becuase I did not check things before I put the motor/box in the car I am now faced with a clutch fork with a pivot point not suited to my clutch/slave setup. I have tried setting up an adjustable linkage between the slave and fork but it ended up working out like this because of the wierd pivot point.

when I have the clutch pushed in the clutch does NOT totally disengage

when the clutch pedal is out it slips like nothing else

So either way I adjust things it one factor gets worse and the other better, rendering the car totally useless. I have decided to do things properly and pull the gearbox and change the fork to a proper genunine one. My question is, are the clutch forks used in 4afe/4age FWD motors the same as the ones used in the RWD ones? I only ask because ive checked at toyota they do no longer sell really anything RWD for a 4age as they are all imported and they will take 3/4 weeks from japan and I cant wait that long. I was thinking as the 4afe/ge FWD models where released in AUS there is a chance that they would have one in stock. Anyway, anyway can anyone confirm or deny this for me? I work in spare parts at toyota but im having a day off today and cbf going in there to check, actully I should just call. ah well

Cheers,
Tom

[Hen]

I have a spare ADM AE86 T50 clutch fork in the shed. It sounds like this will suit. If so send me your address and I can post it down on Monday (if I remember).

Hen

[allencr]

Did the slave cyl. piston bottom out while the clutch fork was still putting pressure on the release bearing & clutch?
Was the slave cyl, piston in danger of popping out when the pedal was on the floor?
Does the clutch fork have a return spring and adjustable stop
for adjusting free play?
If all are no, then making an adjustable push rod for the clutch fork & slave didn't do anything. The clutch gets pushed just as much as the slave piston will move from the master pushing fluid to it. The adjustable rod will only change the position of the piston in the cyl., and not it's length of travel.
If the slave & fork don't line up and the push rod isn't centered, there will be more piston & bore wear in the slave,
and the ratio change will slightly affect the amount of travel the release bearing will have, but it wouldn't have any over all effect on the clutch operation.

Bad clutch/pressure plate and/or/maybe a bad disk.

[Spode]

The clutch line has been bled properly, the pedal box setup I am using works so that there is no stop in the master cylinder (you can push the pedal all the way untill the piston is hitting the end of the cylinder) so I would imagine that yes when the piston in the slave would be close to coming out. When the pedal is in all the way and the linkage is wound out the clutch fork is hitting the back of the hole in the bellhousing, so it cant go any further. Hen, sounds the goods. I will PM you asap.

Cheers,
Tom

[allencr]

OK, that was very important, and there isn't any question unless it's not going to disengage no matter waht the travel.

when I have the clutch pushed in the clutch does NOT totally disengage
when the clutch pedal is out it slips like nothing else

The first statement could be from the fork not moving far enough, but the second statement can't mean anything but a bad clutch, or the result of making an extra long slave push rod that woon't let it engage completely.



How much travel does the clutch fork have before it hits?
It shouldn't need more them 10-15mm at most.

[Grega]

tom i had this exact problem with my 2T and Supra box.
i managed to sort it by adjusting the pedal to the cluster master cylinder distance (thanks toby)
what master and slave combo are you running? there are different size slaves to suit applications (different bore size) to push different amounts of fluid...
when i had my 4AGE in the TA22 the stock master worked fine with a brand new A series RWD slave cylinder (from 4AC powered Ae86)

[Spode]

the clutch not totally engaging when the pedal is out is due to the extra long pushrod wich I have made up, If I make it shorter the clutch will engage properly when the pedal is out but when the pedal is pushed all the way in the clutch will probably not engage much at all or at all whatsoever. The master cylinder I am using is a pretty much brand new one from a AE86 and the slave is from a Aus delivered AE86 so it is designed to run on the exhaust side of the engine. Once I change the clutch fork to one desienged for a T-50 the setup should work like a factory setup. well hopefully

The fork travels about 2cm when the rod is at the length it is at the moment. I believe that the problem is the pivot point of the fork. Its the only thing I can see which is causing the problem as everything else is practially brand new and all to standard spec.

Cheers for your help fellas.
Tom

[jonra23]

Does your current clutch fork fit onto the standard pivot point position and push onto the thrust bearing in the correct position on the clutch fork?

Is the slave cylinder mounted directly to bellhousing and does the pushrod from the slave cylinder push in a straight lline to the clutch fork?

If the answer to both of these is yes then the ratio for your clutch fork is correct.

The other ratio that will effect travel at thrust bearing is the ratio between the bore of master and slave cylinders.

Stupid question last; no air in the system and no freeplay between pedal pushrod and master cylinder?

regards
jon

[Spode]

cheers for all the replys guys, From memory (the motor/gearbox have been in the car for some time now) the clutch fork fits roughly with the throwout bearing. I have spaced the slave cylinder out with some washers because the clutch fork is not suited to this gearbox/slave the indent in the pedal is further out. This is the reason for me using the adjustable rod in the first place so that I could make up for the spacing out of the slave. The rod from the slave to the fork is not totally straight but straight enough that I dont think it would be causing a problem. Before pulling the box I may try drilling a hole in the fork which suits the slave when it is bolted directly to the bellhousing without washers and see if I have any luck.

Oh, and the line has been properly blead, you can feel the clutch move underneath your foot.

Cheers,
Tom

[allencr]

2cm should be way more then enough for any clutch to disengage!!!
Diaphragm spring pressure plates need less travel then an old worn out coil spring type with its levers/linkage, adn even those don't need 2cm..
The stock clutch disk with its wavey spring plate between the front & back friction material is the only reason to have much fork travel, because it has to compress so much before engagement. A performance/racing disk without that only needs 5-10mm.
If the pressure plate is bad, mis-adjusted, or the disk is bent or coming apart, you'll have the same problem - lots of fork travel with poor results.
I definitly wouldn't be trying to get more travel with a larger master and/or smaller slave bore.
The slave, pushrod, fork alignment is slightly important for wear on the slave piston & bore, but is relatively unimportant for whether the clutch will engage & disengage without twice the usual fork travel/movement.