hydraulic clutch

Post by **davesmith** » Sat Jul 11, 2009 11:04 pm

has anyone done a hydraulic clutch conversion with out usin the kit or has any one got any instructions/tips

linearaudio · Post by **linearaudio** » Sun Jul 12, 2009 7:17 am

Don't know! Someone on the board recently referred to the job as "peasy", but didn't expand on it. I would also love to know/ investigate how to do this, for my imminent overdrive conversion. Do you have a link to the kit?

Post by **Alec** » Sun Jul 12, 2009 8:23 am

Hello Dave,

the fundamentals are very basic, but the problem with the Minor is that it is difficult to locate the master cylinder as the pedals are pivoted below the floor. I understand that a Marina pedal box can be fitted but I have no experience of that.
What I did was buy a master cylinder from Demon Tweeks which uses a remote reservoir to feed it. This master cylinder I mounted on the gearbox cross member and used a rod from the clutch linkage to actuate it.
I made up a plate and mounted a slave cylinder to operate the clutch arm ( Note, this is on a Marina\Triumph single rail gearbox.)

I don't know what gearbox you want to use but I certainly wouldn't convert a Minor gearbox to hydraulic just for the sake of it.

It was a straight forward job for me, as I have good workshop facilities and a few bits and pieces lying around to get all those odds and ends one needs for any modification.

Alec

Post by **davesmith** » Sun Jul 12, 2009 2:20 pm

just thinking about it befor i drill holes in the chasis leg i have just fitted esm sells a kit the slave cylinder looks to be the same as a mini one. there seams to be two mounting holes on the side of the 1098 minor bok just by the operatin fork as for the master cylinder that look to be a universal job

Post by **bmcecosse** » Sun Jul 12, 2009 3:52 pm

The Minor clutch arrangement is ideal as it stands - simple/adjustable - and it WORKS. Don't even think of converting to troublesome hydraulic clutch - where's the advantage ?

Post by **M25VAN** » Sun Jul 12, 2009 4:52 pm

I had a hydraulic kit fitted a while ago, nice and smooth and totally self adjusting with a ball race clutch release.
From what I remember the slave bolted onto the gearbox bell housing and operated the clutch release via a short rod. The master fitted into the gearbox crossmember.
I might have the instructions somewhere if anyone wants........

Post by **bmcecosse** » Sun Jul 12, 2009 8:48 pm

The ball race release could be a handy improvement - the gearbox must have been out to fit that - was that necessary to fit the hydraulic slave ? How is it 'self adjusting' ? Does the ball release run against the pressure assembly all the time ?

Post by **M25VAN** » Mon Jul 13, 2009 11:49 am

Ball race is good, in fact that is still on the van and has done well over 100k, probably nearer 150k. I've never had a carbon release last that long!
The race fits the same as the carbon one and is only in contact when the clutch is used so yes box came out to fit.
Hydraulic slave bolted on to two existing holes on gearbox and adjustable rod shortened to fit. This isn't used to do any adjusting, just operate the clutch release so any suitable fixed length bit of rod would work.

So to recap the kit and ball release replaces the cardon thrust release and all of the mechanical links between the clutch pedal and the release fork.
It was definately smoother and lighter but how much of this was due to replacement of already worn components I don't know.....

Post by **bmcecosse** » Mon Jul 13, 2009 11:53 am

Yes - I just don't understand how it is self adjusting - unless it constantly runs on the pressure assembly. Otherwise - how does it know where to 'self-adjust' to ?

Post by **MarkyB** » Mon Jul 13, 2009 6:38 pm

Fluid comes into the system from the reservoir to take up any slack I believe.
Also the moving parts aren't as exposed to road dirt as they are on the mechanical system.

Post by **Alec** » Mon Jul 13, 2009 6:49 pm

Hello BMCE,

yes you are right but there is no real load on the thrust. The adjustment takes place as the slave has a greater depth than required to release the clutch, as the clutch wears the slave piston gradually moves deeper into the cylinder. But it is the clutch that pushes back until there is no load, that is the self adjust point.

Alec

Post by **bmcecosse** » Mon Jul 13, 2009 8:49 pm

That's what I thought - so it wouldn't work well with a carbon thrust - which would presumably wear away very quickly - since 'always' in light contact with the pressure assembly. So - it would have to be gearbox out to fit roller release bearing - if going this route.

Post by **mike.perry** » Mon Jul 13, 2009 9:58 pm

The ball race thrust bearing works well on my manual diaphram clutch set up, along with the linkage modification.

Post by **M25VAN** » Mon Jul 13, 2009 10:09 pm

Sorry I didn't make myself clear when I said

"The race fits the same as the carbon one and is only in contact when the clutch is used so yes box came out to fit. "

This is with the standard clutch linkage not the hydraulic setup. I can't remember how the ball race worked in conjuction with the hydraulics. All I do remember that it was an extra to the kit and was sold as making the clutch setup fully self adjusting.
Hopefully I can find the instructions for a fuller explanation....

Post by **M25VAN** » Wed Jul 15, 2009 6:32 am

Found the instructions.

With the original carbon release everything between the clutch pedal and fork lever is replaced by the master and slave cylinders. Release is held off the clutch by original spring and adjusted by now shortened original rod.
I'll post here when I get it all scanned in.....

Post by **davesmith** » Wed Jul 15, 2009 6:42 am

thanks

Post by **bmcecosse** » Wed Jul 15, 2009 9:09 am

Ahh - ok - so ball release not absolutely required then! And not self adjusting in that mode. Can't see the advantage then really - my clutch is very light/smooth with the standard linkage!

Post by **M25VAN** » Thu Jul 16, 2009 12:46 pm

Finally got the instructions scanned in.....

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Instructions are copied out below as text was very faint. If anyone wants a copy of the original to work from (in case of typo's!) then let me know and I will email it.

"This conversion kit is easy to install and retains the use of the existing Minor clutch pedal. Please read the instructions carefully and understand them before starting work.

Start by removing the gearbox mounting crossmember, all the mechanical clutch linkage and crossover shaft from the car, following the instructions in any Minor manual. It would be advisable to remove the gearbox tunnel cover from inside the car to give easy access for installation. Support the gearbox with a jack throughout this operation.

Fig. 1.

Using the template supplied, enlarge the two half-round cutaways in the crossmember end (driver’s side). Only the rear cutaway needs the two ‘ears’ filed out. (see template).

Fig. 2.

Attach the new master cylinder to the crossmember as shown and refit the assembly to the car. Push the clutch pedal up as far as possible: adjust the clevis on the threaded push rod until the holes in the clutch pedal and clevis line up. Back off the clevis until half a hole is visible and the insert the clevis pin.

Fig. 3.

Using the forward bolt hole in the chassis (one of the two used for the crossover shaft pivot), screw in the long ½” bolt supplied complete with locknut. Hook the new return spring between the bolt and the clevis.

Fig. 4.

Shorten the original Minor adjusting rod to 4” as shown and radius off the end with a file. Use the original locknut and the new ‘ball’ nut supplied.
Now bolt the new slave cylinder onto the bell-housing using the two 9/16” bolts supplied. There are two threaded holes already in the gearbox casing for this purpose. As you do this, insert the shortened rod (Fig. 4.) into the slave cylinder (radiused end) and into the eye of the clutch lever arm coming out from the gearbox. Ensure that the ball-nut is as far onto the threaded rod as possible.

You must now adjust the clearance of the carbon lift race from the clutch. Push the adjusting rod fully into the slave, against the pressure of the internal spring, and hold it there whilst unscrewing the ball-nut until there is about ¼” free play between the arm and the ball-nut. Connect the original clutch return spring in the normal way, pulling the arm towards the slave cylinder.

Fit the long copper pipe between the slave and forward connection on the master cylinder. Secure the pipe against the chassis with two of the ‘P’ clips supplied, clear of any obstructions it may rub against.

Screw the copper adapter pipe into the rearward master cylinder connection. Fix the remote reservoir rubber pipe with clip supplied and run it forward along the chassis leg to the engine compartment where the reservoir unit should be sited in a convenient position.

Fill the reservoir and bleed the system. Check the lever arm adjustment again and lock up the nut.

The clearance adjustment should be periodically checked for correct setting, measurements taken at the lever fork end, NOT clutch pedal free play as is the normal way."

Clear as mud now?