80 series turbo diesel clutch problem

Submitted: Wednesday, Sep 09, 2009 at 11:42

ThreadID: 72135 Views:14455 Replies:7 FollowUps:20

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Bugs

Hi everyone.

I have an 80 series turbo diesel GXL and recently the clutch pedal does not return all the way back up after being depressed.

Have installed an overhaul kit in the master cylinder and this made no difference.

The pedal comes back up about half way instead of coming back up all the way. The clutch still functions ok.

The master cylinder has a damper/accumulator fitted and I suspect this may be the problem. Have tried bleeding the system several times which results in a slight improvement for a while, then it goes back to the same problem. pumping the pedal quickly in succession improves it somewhat, but again only for a short time.

Has anyone else had a similar problem and if someone could shed some light on the cause would be appreciated. I suspect the damper/accumulator but am not sure.

Thank you.

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Reply By: Member - Joe F (WA) - Wednesday, Sep 09, 2009 at 12:10

Wednesday, Sep 09, 2009 at 12:10

G'day Bugs

Have you checked to see if the pedal return spring is still in place, up under the dash ~ just a thought ;)

AnswerID: 382500

Follow Up By: Bugs - Wednesday, Sep 09, 2009 at 12:21

Wednesday, Sep 09, 2009 at 12:21

Hi Joe.

The springs on the pedal are in place, but the pedal is sprung to assist in the downward travel as when I had the master cylinder removed it went straight to the floor. This seems odd as there is no spring to assist it back into the up position. Not sure if there is supposed to be another spring which may be missing, but I do not think so.

Thanks for your help.

FollowupID: 650046

Reply By: fisho64 - Wednesday, Sep 09, 2009 at 13:30

Wednesday, Sep 09, 2009 at 13:30

that seems a little odd, if there was a spring pushing it down it would be same as driving with your foot riding the clutch?

AnswerID: 382507

Follow Up By: Bugs - Wednesday, Sep 09, 2009 at 13:44

Wednesday, Sep 09, 2009 at 13:44

Hi fisho64

Thats what I initially thought too, but according to the manual the cutch pedal is spring assisted with 2 springs and an assist arm. The manual also states that the clutch pedal needs to be raised by hand during the bleeding operation.

Thank you.

FollowupID: 650056

Follow Up By: Hairs & Fysh (NSW) - Wednesday, Sep 09, 2009 at 13:51

Wednesday, Sep 09, 2009 at 13:51

Hi Bugs,
I just went outside to checked mine and it only has one spring on it. and that's to help lift the peddle back up.
I would be thinking all 80's are the same, then again, I could be wrong :)

FollowupID: 650060

Follow Up By: Hairs & Fysh (NSW) - Wednesday, Sep 09, 2009 at 14:05

Wednesday, Sep 09, 2009 at 14:05

Correction, should of read One set of springs,
:(

FollowupID: 650062

Follow Up By: Bugs - Wednesday, Sep 09, 2009 at 14:36

Wednesday, Sep 09, 2009 at 14:36

Hi Jon

Thought I would attach a diagram of the pedal assembly from the manual.

Thanks for your responses.

Joe.

FollowupID: 650073

Follow Up By: Hairs & Fysh (NSW) - Wednesday, Sep 09, 2009 at 15:30

Wednesday, Sep 09, 2009 at 15:30

Yep, thats it.
You have those springs and it still wont return to the up position?
Hmm

FollowupID: 650088

Follow Up By: Bugs - Wednesday, Sep 09, 2009 at 15:33

Wednesday, Sep 09, 2009 at 15:33

Yes Jon, the springs are for downward assist only.

FollowupID: 650089

Follow Up By: Hairs & Fysh (NSW) - Wednesday, Sep 09, 2009 at 15:56

Wednesday, Sep 09, 2009 at 15:56

If all the mechanical bits are where they are suppose to be. and I've never pulled an 80's one apart, maybe a leaky Booster Diaphragm or ?
Image Could Not Be Found
What else helps in the return?

FollowupID: 650092

Follow Up By: Bugs - Wednesday, Sep 09, 2009 at 16:06

Wednesday, Sep 09, 2009 at 16:06

Jon, mine is without the booster, hence the need for the assist springs for the downward motion. I assume the return is handled by the spring inside the bore of the master cylinder, and the return is also handled by the returning fluid which pushes the piston in the master cylinder back.

I think that a fault in the damper which is attached to the bottom of the master cylinder, somehow preventing the fluid return.

Thanks again.

Joe.

FollowupID: 650093

Follow Up By: Member - Kevin B1 (WA) - Wednesday, Sep 09, 2009 at 16:59

Wednesday, Sep 09, 2009 at 16:59

Looks to me like the springs are lifting the pedal with that setup.

FollowupID: 650101

Follow Up By: Hairs & Fysh (NSW) - Wednesday, Sep 09, 2009 at 17:04

Wednesday, Sep 09, 2009 at 17:04

Joe,
When you depress the pedal, and it does not return, do you have to pull it up with your foot?
When returning it to the full height, 1, does it feel like it has resistance, 2, does it feel like a clutch should, has you depress it again?
Maybe a scored/marked bore, if you have replaced all the serviceable parts and the problem is still there, just a thought.

FollowupID: 650103

Follow Up By: Bugs - Wednesday, Sep 09, 2009 at 17:15

Wednesday, Sep 09, 2009 at 17:15

Jon, yes I have to pull it up with my foot. No resistance when it goes back down, except the first half of the downward travel feels very easy then the second half of the down travel actually engages the clutch as is harder. The pedal itself felt ok when I had the master cylinder out. I did the replacement of the piston and seals which come as one unit and easy to replace, and the bore of the cylinder is ok, no pitting or rust and very smooth.

FollowupID: 650105

Follow Up By: Hairs & Fysh (NSW) - Wednesday, Sep 09, 2009 at 19:07

Wednesday, Sep 09, 2009 at 19:07

Hmm, I'm only a bush mechanic and a Wood Butcher, so others that are a lot more knowledgeable than me may know of what is causing it.
Is there any way that you could get hold of a second hand one to test and through a process of elimination, rule it out or in that it's not the clutch itself?
I know it's a lot of buggeizring about. :(
Please let us know when you find what is causing it.
Cheers

FollowupID: 650142

Follow Up By: Bugs - Wednesday, Sep 09, 2009 at 19:27

Wednesday, Sep 09, 2009 at 19:27

Thanks Jon.

No access to another master so I will just plod along and post any result if I get to the bottom of it.

Cheers.

Joe.

FollowupID: 650148

Follow Up By: Grum4wding - Thursday, Sep 10, 2009 at 21:07

Thursday, Sep 10, 2009 at 21:07

Have you checked the slave cylinder??.
If it has no signs of any leaks then try bleeding it. It should gravity bleed easily.
If the master and slave cylinders are ok your problem might be deeper. The pressure plate may have given up the ghost. Are there any noises when you depress the clutch???

FollowupID: 650282

Follow Up By: Bugs - Thursday, Sep 10, 2009 at 21:15

Thursday, Sep 10, 2009 at 21:15

Hi Grum4wding

Yes have checked the slave, no leaks and I have gravity bled it.

Pressure plate and clutch are genuine toyota and done about 50,000k mostly on road, original lasted around 170,000k. Clutch feels ok otherwise and no noises. My suspect is the damper attached to the master cylinder, but not 100% sure. Will keep all posted if I solve it.

Thanks for your response.

FollowupID: 650286

Reply By: Member - Rob S (NSW) - Wednesday, Sep 09, 2009 at 16:52

Wednesday, Sep 09, 2009 at 16:52

Hi Bugs
Had a similar problem with mine and i think the petrol's are the same set up.
The pedal wouldn't return all the way.
I just replaced the complete master cylinder gen Toyota $150.
I got my use out of the old one
All fixed and piece of mind as you don't need that to fail in the never never.

Check the slave cylinder the piston can be rusted up and not returning completely ,a seal kit would be ok not much to go wrong there, as long as there is no deep pitting in the cylinder.polish the bore and piston with a brillo pad.

Rob.

I only ever made one mistake
and that's when I thought I was wrong!

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AnswerID: 382524

Follow Up By: Bugs - Wednesday, Sep 09, 2009 at 17:18

Wednesday, Sep 09, 2009 at 17:18

Hi Rob.

Thanks for your response.

I am tempted to replace the lot, but just trying to make sense of the problem seeing the bore in the master is ok and I put a new piston with seals in it too. Felt ok on the bench too. I strongly suspect the damper attached to the bottom of the master. But I will get in there and check out the slave too as I have not done that yet. Also there are no apparent leaks on either cylinder.

Joe.

FollowupID: 650106

Reply By: Member - Kevin B1 (WA) - Wednesday, Sep 09, 2009 at 17:03

Wednesday, Sep 09, 2009 at 17:03

Your problem could also be in the clutch pressure plate. The springs in the pressure plate may have failed or be on there way out.

AnswerID: 382526

Follow Up By: Bugs - Wednesday, Sep 09, 2009 at 17:24

Wednesday, Sep 09, 2009 at 17:24

Hi Kevin.

Thanks for your response.

The clutch has been in for about 4 years and 50,000ks and is a genuine toyota. Dread the thought that it has failed, though anything is possible. Most driving on road, and no serious off road.

The original clutch lasted for 170,000ks and still worked ok when replaced, just did it as a precaution.

Joe.

FollowupID: 650108

Reply By: Member - Kevin B1 (WA) - Wednesday, Sep 09, 2009 at 18:47

Wednesday, Sep 09, 2009 at 18:47

OK try this,, With engine running, transmission in first gear, foot on brake then slowly release clutch at the same time give the engine a few revs. If the clutch does not engage until the pedal is nearly fully released or slips when fully released it will prove one way or another if the pressure plate is on the way out. If it`s OK it will reach friction point about half way out then grip and not slip.

AnswerID: 382544

Follow Up By: Bugs - Wednesday, Sep 09, 2009 at 19:25

Wednesday, Sep 09, 2009 at 19:25

Ok will give that a try, but the grip seems ok, no slip evident, even when uphill in 4th or 5th gear.

Thanks again.

FollowupID: 650147

Reply By: Darrin - Thursday, Sep 10, 2009 at 22:40

Thursday, Sep 10, 2009 at 22:40

Hi Bugs
I had a similar problem with the wifes camry. Found the problem to be the slave cylinder.

AnswerID: 382699

Reply By: Bugs - Friday, Sep 11, 2009 at 13:43

Friday, Sep 11, 2009 at 13:43

Hi everyone.

Problem Solved.

It was the clutch damper, the piston inside it had gummed up and seized.

I removed the damper housing and blocked off the port to the damper using a small copper disc. Then replaced the damper housing without the internal piston and seal.

Clutch pedal now returns all the way up.

Anyone else with a damper on the clutch master cylinder who has similar problems can do the same or just find a large enough bolt to replace the damper housing altogether.

A big thanks to everyone who has responded, very much appreciated.

See you in the bush sometime.

Cheers.

Joe.

AnswerID: 382763