MIdget Clutch- Totally stumped.

[slowduke]

Hello Ladies and Gents

Some help on the following would be much appreciated:

1972 RWA Midget.

Had porblems with the clutch not disengaging properly.

Thus I have replaced the cluct release bearing, as it was in bits.

New slave cylinder an it was leaking. These two fixes got it working after a fashion but not as well as it should, I then replaced the master cylinder push rod and clevis pin to remove wear there.

I then decided to re bleed the system, I know there is a lot on here about the 'fun' involved in this but having searched I cannot find this specific problem

Basically I ran about 1.5 litres of fluid through the system using an eazi bleed ( by this point I too was bleeding a little)

The car was on ramps at the front to make sure that the bleed nipple was uppermost.

Jumped in car, pedal was a firm as a firm thing, happy days.

I started car, while on the ramps, clutch in and all gears selected beautifully.

I then realised that the eazi bleed was still connected, took that off tidied up and went for a drive.

Actually I then discovered that I could not get reverse, the pedal had no resistance untill the bottom inch, so I did it again,

Basically while the eazi bleed is connected the clutch is fine as soon as I disconnect it, the pedal goes.

I have no apparent leaks anywhere, my first thought was air still in the system, but as the tyre providing pressure is only at less than 1.5 bar I would not have thought this would be enough to squash any bubbles in the fluid.

( This thought struck me while doing a 6m deco stop on a dive at the weekend, I was at 1.6 bar and off gassing at this point, so less than this should not be enough to compress bubbles in clutch fluid?)

I must have missed something obvious, it someone could tell me what it is, I would be very grateful!

Thanks

Russ

 

[nomad]

I could only guess that something has failed inside the master cylinder. Adding a little pressure makes it work but without the fluid is getting past the seal's? Just guessing....

Kurt.

 

[JPSmit]

My thought is that the clutch fork itself might be bent and that the extra pressure gives that fraction it needs.

 

[JPSmit]

Or, how old is the hose? Could it be ballooning?

 

[slowduke]

Thanks guys, fork was checked when bearing was replaced, hose was fitted by PO but looks pretty new. Fitted a new MC this evening, the only thing that has bled was my head when I banged it on the chassis trying to get out of the way of a torch falling off the chassis rail where I had wedged it to see what I was doing ( I know about the access from the footwell, but cannot get the bung out) Am going to try back bleeding tomorrow if I can get a syringe. I have put a couple of pints through it tonight using an eazi bleed and there do not seem to be any more bubbles. I could take it to a garage, but that would be admitting defeat!

 

[Sarastro]

Sounds a little extreme for this, but I'll make the point anyway--this is the kind of thing that can happen if the adjustment for the master-cylinder pushrod isn't right. As you push the pedal, fluid just goes back into the reservoir until the piston passes the return hole. If the adjustment is too tight, you go too far before the piston passes the hole. Maybe with the easybleed in place, it prevents the fluid return so it seems OK.

My experience is with bugeyes, and I know the MC has changed on the later cars. So, sorry if this doesn't seem to make any sense, but the principle applies to many kinds of cars.

 

[aeronca65t]

Clutch push rod are two different lengths (both are fixed length). Older ones (948 and 1098) are shorter. 1275 push rod is longer. Maybe someone swapped in the wrong one?