Dolly 1300cc clutch

[TerryC]

Hi all, Got into Dolly this morning to go out and my foot went straight to the floor, clutch gone? Where is the most obvious place to look Master cylinder or slave cylinder. All help appreciated
Many Thanks
T

[xvivalve]

If it is the seal in the master that has gone the fluid will have leaked out the back along the pushrod and if you run your hand up the clutch pedal to where the clevis pin attaches the pushrod to it you'll likely encounter fluid. If you don't find any fluid there it is most likely the slave that's your problem.

However, I have found previously that replacing only the seals in one of the cylinders usually makes the other the weakest link (and as Sprints in particular can be difficult to bleed) I now tend to replace both seals and bleed once.

If you need a new clutch slave go to David Manners (Abingdon Parts for Triumph) as they put in the leg work to resolve the issues with 1300 and 1500 type slaves.

[TerryC]

Thanks valve for the reply. I've just got around to doing the job. It was the slave. What a bitch to bleed. Who designed the feed on the bottom and the bleed on the top? It would be so much easier to bleed if they were the other way around.
Many thanks
T

[cliftyhanger]

If the bleed was at the bottom, the slave would be VERY hard to bleed as the air would stay at the top! People often remove the slave off the gearbox to bleed it.

[Carledo]

If the bleed screw was on the bottom, the job would go from difficult to impossible, since air in a fluid rises naturally, you'd never get all the air out!

A Sprint slave also bleeds from the top, but the cylinder itself is angled downwards at the back, trapping air in the upper forward portion of the slave. Best trick is to jack the rear of the car as high as possible to level out the slave before bleeding. This can even help a tad on a car with a level slave.

Steve

[xvivalve]

Thanks valve for the reply. I've just got around to doing the job. It was the slave. What a bitch to bleed. Who designed the feed on the bottom and the bleed on the top? It would be so much easier to bleed if they were the other way around.
Many thanks
T

Exactly why I replace cylinder seals in pairs…it’s most disheartening when the master fails after a couple of weeks from doing the job, though I have managed to change a master cylinder without needing to bleed it…once!

[TerryC]

Now I've learnt something new that I never thought about. Thanks all for your responce.

[Jod Clark]

OK, I'm going to be a bit controversial here, but bear with me. There are also some caveats to what I'm going to type, so I'll begin with those.

I am not sure if all Dolomite OHV slave cylinders have the same tappings for fluid union and bleed nipple, but some of them definitely do. If yours has differing tappings then this won't work.
This will only work if your car has the original plastic (usually red) pipe between master and slave.

In my experience the best way to fit the slave is with the fluid inlet at the top and the bleed nipple (not used for actual bleeding) at the bottom. The circuit can then be self-purging.

How to do it.:

1: Fill the master cylinder with fluid, open the bleed nipple just a little bit. With the aid of a glamorous assistant, depress the pedal full stroke and close the bleed nipple when fluid begins to emerge.

2: Allow the pedal to return to the top and rest for a moment.

3: Reposition glamorous assistant to observe the fluid hose at its highest point.

4: Slowly push clutch pedal to the floor again and hold it there. Glamorous assistant should see air bubbles and fluid passing towards the slave cylinder. Hold the clutch pedal at the floor. Assistant should see air bubbles rising in the pipe from the slave cylinder towards the highest point. When there's a good bubble in the pipe at the highest point, allow the pedal to return to the top. Pause for a moment.

5: Repeat step 4 until no more air bubbles are observed in the pipe.

6: Drive around.

This works with the original plastic pipe because of its large diameter which allows the air bubbles and fluid to swap places in the pipe and also because the amount of fluid in the pipe between the master cylinder and the highest point of the fluid pipe is less than the amount of fluid displaced by the master cylinder. With additional strokes of the pedal the system will continually self purge.

So put the bleed nipple at the bottom and the fluid union in the upper position on the slave cylinder. Thank me later.

[Richard the old one]

Hi Jod.

I found your article interesting to read and I can understand that you have found that it works however after checking my spare slave cylinder a part number GSY105 it does have different size treads so I would not be able to install it as you suggest.

I believe that a GSY103 is notched on the other side so it could be installed and connected as you suggest.

Many thanks for the tip.

Richard