Using longer pushrod for clutch slave cylinder...A Bad Idea?

[mullett]

Got problems with my clutch on the MR2 after fitting an excedy aftermarket one, basically the clutch only actuates on it in the bottom 1/3rd of its travel, not nearly far enough to disengate it. I've checked all the lines and bled them, it's all good. By ghettoing a bolt into there (about 15-20mm longer than the pushrod) it seems to work fine. Basically, just wanting to know if there are any hidden pitfalls (like the bearing being pushed too far) that I should be wary of...

Cheers, RM.

[takai]

Shouldnt be any problem. Infact if you go to a brake place and ask nicely you can probably get an adjustable pushrod for your slave. I will be running a longer rod on my race car as i occasionally pop the piston out when i get fired up.
If you think abotu the hydraulic system then the distance that the piston is resting in the bore doesnt matter overly, it is merely the range of movement it has. Also most pistons will have a rest so they cant slip down too far into the bore and block off the feed.

[willwal98]

Have you adjusted the pedal out?

[Mathew]

not sure about the MR2 setup but have had simmilar problem with other vehicles - check the clutch fork pivot - does it have an adjustment - inside the bellhousing should be a ball ended bolt with a nut - undo the nut and adjust up and down till clutch "throws " properly!
cheers

Mathew

[mullett]

yup, I remember seeing that, but buggered if I'm going to take the gearbox off again if there's an easier way...that's HEAPS of time to do that, with everythign around it...Good suggestion though...

Cheers, RM.

[inertia]

Don't know about the MR2, but we had that exact problem with my AE92 gze conversion and the heavy duty clutch.

rallystanza brought the pickup point on the pedal up by adjusting the threaded U piece on the master cylinder shaft (wound it out I think). Also adjusted the pedal spring etc to suit.

Works a treat in winter, though can sometimes be close to the floor in winter/cold mornings for some reason

[bobob]

I have experienced a similar problem. After changing clutch / pressure plate / bearing the pedal did not provide enough travel (even after adjustment) to disengage the clutch.

I bought a 30mm long nut (some joiner of some sort) and welded that on the end of the existing U nut thing on the back of the clutch pedal. This seemed to fix the problem as I now had enough adjustment to get it how I wanted it.

Talking the people that provided the parts, while getting a clutch for another FWD 4AGE they advised that there are different bearings with 3 different heights. I think that I may have used a shorter one, effectively increasing the required throw.

EDIT:

If you do go for the longer throw, dont people say that you should be wary of your seals and what not as that last part of the cylinder is rarely used and can be gunked up / corroded. (I rebuilt master / slave as part of the troubleshooting)

[Hen]

I have used a length of steel rod for over a year no problems. I just cut it to the length I wanted and rounded off the ends so it sits nicely in the clutch fork and slave piston.

Works perfectly.

Hen

[takai]

If you do go for the longer throw, dont people say that you should be wary of your seals and what not as that last part of the cylinder is rarely used and can be gunked up / corroded. (I rebuilt master / slave as part of the troubleshooting)

Slave cylinders are disposable
$30 from my local repco, ive gone through 2 slaves and a master, not including the master which got taxed.

[Squid]

mullet - a lot of GT4's were having this problem after installing a hd clutch and it turned out to be a broken pedal box, might be worth investigating...

edit :just realised you have a AW11 and the similarities may not be there...

[mullett]

Yep, had a look around, no-one's ever heard of an adjustable one. I think I'll just get a length of 4140 steel and cut it to size...

CHeers, RM.

[takai]

The PBR ones come with one stock, im buying a new one tomorrow so ill take a photo then.

[bobob]

Can you adjust the rod on the back of the pedal rhat pushes the master to get some adjustabliity?

[mullett]

The PBR ones come with one stock, im buying a new one tomorrow so ill take a photo then.

Do you know if that is availible to suit the AW11 with E51 box? I might as well get a new slave cyl...

RM.

[allencr]

It won't do a BIT OF GOOD, unless it's like takai's problem with the piston popping out. Nothing can adjust the length of travel since it will ONLY move as much as the amount of fluid the MC displaces in it, and nothing more. Adjustable pushrods only work on designs that have a spring on the clutch fork that bottoms out the slaves's piston.
The fork pivot point adjustment would be very good IF the fork was making contact with the bellhousing. It isn't is it?
How much freeplay is there???
Like others have said, adjust the freeplay at the MC, inspect the pedal box, or get another clutch.

[Toobs]

It won't do a BIT OF GOOD, unless it's like takai's problem with the piston popping out. Nothing can adjust the length of travel since it will ONLY move as much as the amount of fluid the MC displaces in it, and nothing more. Adjustable pushrods only work on designs that have a spring on the clutch fork that bottoms out the slaves's piston.
The fork pivot point adjustment would be very good IF the fork was making contact with the bellhousing. It isn't is it?
How much freeplay is there???
Like others have said, adjust the freeplay at the MC, inspect the pedal box, or get another clutch.

Wrong.
A longer pushrod will push the slave cylinder further back into its bore allowing about half a cm more travel.

[mullett]

I'm going to give you some rep for that comment, because you're bloody right. If only i'd read it earlier...I made up the longer rod, It made not the slightest difference. oh dear...this could get to be nasty. If something stupid like the clutch starts to hold me up....damn.

[takai]

Wrong.
A longer pushrod will push the slave cylinder further back into its bore allowing about half a cm more travel.

Yeah, but if the MC doesnt push enough fluid then you wont get any more travel.

Sounds like you need a new MC mullett. Possibly check the sizings on each, they might be mismatched (i.e. master smaller than slave) which woudl cause lack of travel. I have the opposite, bigger master than slave, hence more fluid flow, and hence more travel...

[willwal98]

have you tried adjusting the bracket on the clutch pedal yet? There should be a threaded rod with a "U" shaped bracket that joins onto the pedal. Just wind it out a bit and you should get beter pedal postion.

[allencr]

HOW MUCH FREE PLAY???
Besides adjusting the pedal's clevis/pushrod for contacting
the clutch MC piston to remove any slack, it can be adjusted a bit(or maybe more then a bit) until just before it just shuts off the little valve in the end of the MC. This'll give you the MAXIUM amount of clutch fork travel you'll ever get with the MC & slave sizes you've got. You'll know you've adjusted it too far/much, when you're unable to push the slave piston & push fluid back into the reservoir.

Bad pressure plate and/or disk is coming apart.