Hillman Super Minx clutch hydraulic woes...

WarrenL

WarrenL

Active Member
Gidday team,

Some of you might recall that a few months ago I did a labour swap with my painter/panelbeater friend. He's repairing my tragically bent bonnet (still a work in progress) in return for which I put a "new" engine into his Hillman Super Minx. Things have been moving slowly; we were waiting on a few parts, and then I started a new job, whilst Dave's workshop has been crazy busy. Now on the last leg, I've run into trouble. I can't get the clutch working!

- The clutch itself is not jammed. We tested that.
- The master cylinder has been re-kitted and pushes a nice little geyser of fluid out of the end of the hydraulic line.
- The slave cylinder won't push all the way.
- I've opened up said slave cylinder and it looks OK to me, nice and clean, with seals in good nick.

The problem is, I'm not a mechanic, and therefore I've run out of ideas. How do I go about identifying the problem?
 
Is it possible that the cylinders are miss matched ? I.e. the master isn't big enought to fully fill the slave ? Just thinking due to the engine swap.

The more basic issue could be that there is still some air in the system, further up near the master, so although you get a good squirt out of the slave, when you apply a load the air compresses limiting the throw of the slave.

A final option is that the master seals are collapsing under load, letting the fluid past.

On 800's it's often very difficult to bleed the slave, and I often have to remove the slave and manually fill it with fluid, holding the piston back to ensure it is full, then fit the hydraulic line making sure there is no air in the line as well.
 
Is the slave cylinder going to the end of it's stroke without the clutch disengaging ?Can you then move the release arm further with an ironbar ?
What engine was in the car originally ? What have you put in it ? Which gearbox and clutch assembly are you using ?
 
Cheers fellas! To answer your questions in no particular order:

The engine that came out was a 1600. A 1725 went in. I put the slave cylinder from the 1600 on to the 1725 because it was in better condition. I pulled both apart, and they appeared to be identical units.

Dave and I bled the bejesus out of the system, so I would be very surprised if there was still air in there somewhere. The master cylinder is simplicity itself, and there isn't much scope for air to remain trapped somewhere. I also rekitted it, so it should be in good.

I might have to pop in some time in the next couple of days and check just to make sure I'm describing the situation properly (it's been a couple of months since I last played with it), but IIRC, the clutch pedal seems way too soft, and the slave piston doesn't fully extend. That sounds like air in the system, but given what I've said above about bleeding the damn thing until the cows came home, what Richard says seems to make sense. Now Richard, I was getting a good squirt of fluid out of the slave cylinder nipple, but can that still mean the cylinder wasn't actually filling properly?
 
It still could be a problem with bleeding. I found the system on my P6 difficult to bleed. I kept getting an airlock in the slave cyl that wouldn't clear with the cylinder bolted to the car. In the end, un-bolted the cylinder and oriented it so I could bleed the last of the air out, then re-bolted it to the car. Do you have a photo of the slave cyl on the car?
 
No I haven't, but I can certainly go and take one and put it up as soon as I get a chance to get into the paint shop. Not sure when that might be because work has been too busy to find a gap in the day for heading over to that part of town, and Dave hasn't been there on Saturdays lately, but I can always revive the thread. Recalcitrant air in the slave cylinder certainly sounds a likely theory.
 
There could be an air bubble somewhere in the system and the fluid is seeping past it rather than carrying it out of the bleed screw. I'd be tempted to try a pressurised bleed kit as well as detaching the slave cylinder.
 
Hmm, that'd probably involve buying one. I don't know anybody who has such a thing. Are they expensive?
 
Not knowing the layout of the minx slave,is the bleed nipple top or bottom of the slave?
If bottom you most likely have an air lock!If so can you turn the slave so its at the top?
Unless there is a difference in the flywheel and clutch mechanism on the 1600 and 1725!
 
There were two types of clutch fitted to Super minx series,

MkI , MkII & early MkIII 1600 super minx was fitted with a Borg & Beck HA2515 (cover),HB1333 ( 8in driven plate),HD3301(carbon release bearing)
The later MkIV 1725, HE2836 (cover),HB2345(7, 1/2in driven plate),HD1069(carbon release bearing)

It is important to know where the "new" 1725 originated from,...was it Super minx or the later "Arrows" model, :?: ,or a PB Commer
Clutch hydraulics are the same throughout the minx range, the pedal pressure is very light and precise,

Here's a pic of mine that I regretfully sold just recently after 18 years of ownership :(


britt 1999 by CharvilChancer, on Flickr
 
It's an early Minx 1725, not an "Arrow" version; I helped remove it from the very tidy but sadly rear-ended donor car. As I mentioned earlier, the slave cylinder is off the 1600, but having opened up both of them, it's clear that they're identical.

Also, having read over what the others have said so far, the problem seems to me to be air related, rather than connected to a difference in the clutches. The piston has trouble extending, rather than having trouble pushing the clutch lever.
 
Master cylinder faulty ? Can squirt fluid when there's no resistance to flow but not when there is ?
You haven't put the main seal in back to front , have you ?
 
Good thinking, Dave. I'm sure that I put everything back together properly (I had an exploded diagram in front of me at the time) but nothing should be discounted, especially my own ineptness. If the manual filling or pressure bleeding doesn't work I'll go back to that.

I'm not sure when in the near future I'll have the opportunity to try all this out. It could be some weeks, but I will report back of course, and in the meantime keep it coming! I want to tackle the problem fully armed with ideas, and you guys have been fantastic so far.
 
One little trick - but I don't know whether it will be possible with your Minx - is to have the slave in particular, but the master as well if possible, detatched from the car so that you can hold them in the best possible alignment for air to rise upwards to the bleed nipple (clearly the reservoir still has to be feeding fluid to the master!). Then once bled, refit to the car.

Chris
 
hi , heres one i did earlier, volvo amazon brake master cylinder , rebuilt the cylinder , working ok but half way around the block the brakes come on on their own , i stripped the thing down half a dozen times before i spotted what i did wrong, the plunger and seals etc were ok but the washer with the slot in it that finally goes on after the pushrod and effectively holds the pushrod in is dished and i put it in the wrong way around , i couldnt tell from the manual and it looked like it should go the way i did it but i was wrong and consequently the cylinder was pre pressurised a little and when warm locked the brakes , i was thinking that had you done the same in either cylinder then you wouldnt have enough cylinder movement to operate the clutch,just a thought , good luck,rich
 
Thanks Rich. It's good to know how these little mistakes manifest, it helps to isolate the problem. As always, I'll test the simplest things first, so initially I'll try prefilling the slave cylinder and perhaps pressure bleeding it (if I can obtain a kit). I was hoping to get there today/tomorrow but Dave's away for Easter so the workshop is all locked up. Meantime, keep the suggestions coming...
 
Finally pinned Dave the painter down - he's working late tomorrow night (Thursday), so I'm going around after dinner to have another go at the Hillman clutch according to the tips above. I'll report back! Might even get a glimpse of my V8 under its dust cover behind all the other cars cluttering up the workshop.
 
Progress!

Well team, progress! I finally managed to coincide with Dave having an evening session down at the paint shop and went along for another crack at that clutch, taking along my pal Ben to do the pedal pushing. I unbolted the slave cylinder, hung it so that the nipple pointed skyward, and commenced bleeding. The second push of the pedal jettisoned quite a bit more fluid than the first - a clue? We pumped a decent amount of fluid through the system and then I remounted the slave cylinder. We now have much more feel in the pedal, and about a 1/2" movement out of the piston. So maybe the air-trapped-in-the-slave-cylinder theory was correct?

Unfortunately it appears the clutch might have seized, so we left it at that. It is a school night, after all. Dave's going to try a crash start and then we'll do a bit more bleeding on another occasion.

Question is, is half-an-inch about right? Or should we be getting more travel?
 
Well, yes. I think. There's a little slack at the beginning as the cylinder piston takes up against the pushrod, and then what I thought felt like even pressure all the way through until the pedal touches the floor.

It's just I'm quite inexperienced at these things and unsure if that half-inch is enough to operate the clutch properly, and of course we couldn't test it properly last night. At least I've made some progress, at long last!
 
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