Bleeding clutch

[JD]

Hi all.

Having a hard time getting any pressure on my hydraulic clutch. Hooking it back up and have pushed a lot of fluid through the bleeder on the slave cylinder. Doesn't seem to burp any air, but piston travel is short. Pressure doesn't seem right at all. Perhaps I'm using the wrong method. Trying to do it as I would brakes.
Suggestions?

JD

[Bern B]

Hey JD

They can be tricky I used a couple of liters of fluid and a day and half to bleed on the 110 also had to adjust the master and clutch pedal.

good luck I know its frustrating we had air trapped up in there somewhere it took forever to get out

Bernie

[JD]

Bernie,

Thanks for that. Thought I was being even more of a dufus than normal. Broke the pushrod to lever arm clip by accident too yesterday. Grr. What was your final solution? And how did you make those adjustments you refered to?

JD

[red90]

How exactly are you bleeding? They can be very fiddly.

[JD]

Red90,

Pedal downstroke, slave cyl valve open, pedal bottomed, valve closed. Pedal up. repeat. Tried doing it ala brakes where several pedal pumps are done prior to pedal down valve open etc. Have tube on valve opening going into tin. Went through 1/2 bottle of dot3 still very little travel on push rod. No air burping out, but lots of dirty fluid. ... which is odd in itself as fluid was all new last Sept.

I'm thinking of taking slave off bell housing to point valve more "up" and see if that helps.

What can I do to improve the bleeding process?

JD

[red90]

Don't open valve until you have started pushing and close before it bottoms. Raise pedal slowly. Sometimes the slave seals are marginal and suck air back in.

[Rob]

Hi JD

You mentioned lots of black fluid... is a flexible rubber-type hose as part of the hydraulic line going to the slave cylinder? If so, check the condition of it as it might be worn out and expanding under pedal pressure causing less travel in the slave piston (have had that experience with rover brakes before). I assume all of the clutch hydraulic components are in good shape?

Something I found to work very well with series brakes instead of pumping the pedal was cutting-up an old tire inner tube keeping a large, circular section of tube attached to the valve stem. I would fill the reservoir with fluid then stretch the tube over the reservoir clamping it with a large hose clamp (must be an airtight seal). I would use my compressor to pressurize the system with air then open the bleed valve at the individual cylinders. It is a little tedious and needs to be monitored to prevent the reservoir from getting too low but the steady pressure and ability to bleed the system unaided is very handy. Might work for your clutch problem.

Regards, Rob

[John]

Sounds like part of the problem is you have used thw wrong brake fluid and the seals are shot (black fluid you have described). Original Girling rubber brake/clutch seals are destroyed by using regular North American types of brake fluid. You should be using ONLY Castrol/Girling GTLMA brake fluid.

[JD]

Thanks for all the thoughtfull replies

John: black stuff certainly seems it might be disolved rubber... but in six months from new? And where is the fluid you quote available?

Red90: We'll try that action next time we go out there. Thanks

Rob: Rubber line looks good on the outside, I'll check expansion when we do this next and see what the pipe looks like. It will be an easy replace if it is ballooning.

I'm sorry but I forgot to post the vehicle type ... which is an MOD 110. Hope that helps any other readers. I did find a comment out on the web that suggested using a hose from the bleeder nipple that rose above the bonnet level before going back to the jar. In this process, the bleeder valve was to be left open all the time. I think the theory is that the levels in the MC and bleeder hose would eventually find equalibrium. Interesting idea.

JD

[DaveB]

Sounds like part of the problem is you have used thw wrong brake fluid and the seals are shot (black fluid you have described). Original Girling rubber brake/clutch seals are destroyed by using regular North American types of brake fluid. You should be using ONLY Castrol/Girling GTLMA brake fluid.

x2

I believe DOT 4 is the equivalent over here. I know, when I replaced all seals and hoses and went to DOT 4 the dreaded black fluid stopped.

Dave

[John]

JD,

Make some calls, most auto parts stores (Auto Parts Plus, Lordco, etc.) should be able to get it for you if they don't stock it. Specialty British shops will definitely have it.

[red90]

A 110 should not need special fluid.

[Bill E.]

Big topic, not so sure about DOT 4 and I am certainly no expert. Curious about red90's comment that "a 110 should not need special fluid". I've been told by those in authority that, like John says, Castrol GTLMA is the way to go. One thing is for sure, it works. Any old British rubber seems to suffer using other fluids. Any short survey of owners at the Van Duesen ABFM will confirm this. You'll likely only get disagreement from those owners with six pump brakes and a puddle under their master and slave. Which brings up another interesting discussion, what is with this sado-masocistic automobile terminology :twisted:

[Roverworks]

To be found in every Lucas-Grilling replacement part box (you purchase from us) is a small publication # XZB127A. In this publication are the following abbreviated instructions:

….“Use Lucas universal brake fluid DOT 4 or Dot 5.1 in Lucas car brake systems and DOT 3 or 4 in Lucas commercial vehicle systems, as recommended. If in doubt consult vehicle hand book.â€

[JD]

Thanks to everyone. Lots to go look at this eve.

Rgds
JD

[red90]

The 90/110 workshop manual says......

"Universal brake fluid complying with DOT 3."

The whole LMA thing is from old Series vehicles with god knows what for seals.

[Bern B]

Hey Hows it going JD did you get all the air out?
NAPA auto parts carry the Castrol LMA I usually get a case of the small containers. When it comes to your clutch and brakes why would you not use the best. All Land Rovers are special
Here is some advice that was given to me when I had the same problem
- It may be necessary to pressure bleed the clutch, If you don't have a pressure bleeder, try reverse bleeding (remove the slave cylinder while connected and push piston all the way in then refit and try clutch.

Bernie :1tonpull:

[Bill E.]

For what it's worth,
:spinning:
Info from Castrol's web site regarding GT LMA

Exceeds DOT 3 and DOT 4 requirements.
Unique Low Moisture Activity (LMA) formulation provides maximum protection against vapor lock brake failure.
Maintains a higher boiling point than conventional brake fluids (Minimum dry boiling point of 311°F
Superior protection against chloride and zinc corrosion of braking system parts.
Ideally suited for Audi, BMW, Jaguar, Mercedes-Benz, Porsche, Saab, Volkswagen, Volvo, Honda, Acura, and many other brake systems.
Exceeds specifications SAE 1703, SAE 1704, ISO 4925, JIS K2233 and FMVSS No. 116 DOT 3 and DOT 4

The following Info from FAQ site on older British cars 70's and earlier

British brake & clutch systems use natural rubber components which are only compatible with vegetable based brake fluid. American brake & clutch systems use synthetic rubber components which are only compatible with mineral based brake fluid. The only vegetable based brake fluid commonly available in the US is CASTROL GT LMA. Use of improper fluids or mixing of fluids can lead to complete failure of brake and clutch hydraulics.

Like Bernie says, why not use the best? After all its not like you buy this stuff by the gallon! Better to spend a couple of bucks on better fluid instead of hundreds on master/slave/wheel cylinder rebuild or replacement.
:spinning:

[JD]

Finnally got consistant pressure and can hear something creak in the bell houseing. Adjusted the pedal height above the floorboards as per the book to 5.5". But when I swing the engine with the clutch pedal depressed to the floor, the propeller shaft flanges turn.
Is this normal? Might this mean that I still haven't got enough movement in the push rod at the slave cyllinder? Or might there be a set up problem with the clutch itself inside the bell housing?

??
JD

[red90]

"Swing the engine"?? What does that mean?

Are the propshafts not connected?

[JD]

Singing.. turn the engine by hand... reminded me of starting a sopwith camel.. not that I've ever done that but always wanted to know how to start snoopy's dog house....

prop shafts not connected.

JD

[Rob]

Hi JD

Has the truck been driven lately? If not, have you considered the possibility of rust between the plates in the clutch from sitting in a damp environment limiting the travel - possibly seizing the plates together? I had that problem with a series two that had been left to sit for quite awhile in a farmers field... had to drive in low gear and put on the brakes pretty hard a few times (gas pedal to the floor) before it let go and started to function normally: just a thought (I think it is also an old mechanic’s trick for checking for clutch slip… not easy on the vehicle from what I understand).

Good luck, Rob

:happy3:

[JD]

Rob,

Yes the thought occurred to me. I'm in the middle of a 300Tdi installation and through one thing and another it is taking quite a while. This clutch was last opperational in Sept. It has sat "dry stored" since then but it sure has been damp - air wise! I haven't yet connected up the engine to anything else deciding to make sure the clutch hydraulics were working first. Little did I know what a challenge it would be. We've pumped and bled and replaced parts and now three weeks later I've got what feels like good pressure, a creak in the bell housing but the propeller shaft flanges turn when I swing the engine with the clutch pedal depressed to the floor. I don't want to assume all will be well and hook up the rest of the engine if there's something that will require splitting the engine and trans again. At this point, as much a PTA as it is it will be easier than at any other time as nothing is connected and the fenders are off.

Thoughts anyone?

JD

[Rob]

Hi JD

Is the clutch aligned properly?

I am not famaliar with the swap you are doing but I did have a problem doing a Ford 302 conversion in a series truck (a kit that Atlantic British used to sell). I installed a remanufactured presure plate and it would not totally disengage... turned out that the disk had been made too thick for the space allowed by the Ford to Rover bellhousing adaptor... could space be a problem in your case?

Regards, Rob

PS: The 302 was wild... could climb trees if you'd let it... always kept a supply of axle shafts onboard though.

[JD]

Rob,

Thanks. Don't think that situation would apply in this case as it is a Land Rover engineered set up.

JD