project 1980 Austin Princess

[High Jetter]

You're probably aware that GMC1007 is a Unipart number (Genuine Master Cylinder). NOS would be worth considering as you have seal kits on order, but they'll probably sort it out anyway when you eventually get them.

[vulgalour]

I did not realise GMC was a Unipart number, new thing learned.  There's variations on the GMC cylinder's number with certain letter suffixesl, though I'm not sure how it changes application other than a couple of different reservoir designs.  I'm hoping the one I've got has only suffered failed seals and I can pop some new ones in and it's sorted, though it's possible the body of it is actually shot too.  Haven't been able to find NOS ones in my online hunting yet, though I'm keeping an eye out. Also, given that the brake master cylinder has been treated to the same black paint as the clutch master, I'm expecting that to be the next item to fail.  Fortunately I do have an original brake master in my spares stock that I'm tempted to send off for testing and refurbishment and swap over just for the security of it.

[vulgalour]

Let's do the clutch master cylinder rebuild!  First, fight with the crusty bolts holding it to the bulkhead, painfully aware that access is not great and spanners will try super hard to round the corners off nuts.  End up literally sitting in the engine bay because it's the only way to get enough force applied to a couple of the nuts.  Eventually, you have this crusty thing off once it's disconnected from the clutch hose and the master cylinder.

You also reach up to the top of the clutch pedal, push out the split pin from the clevis pin, and watch as the bracket for the master cylinder falls out of its place and tries to get lost behind the pedal box.

Then see all the paint that's lifted because the master cylinder has been leaking.  Some of this paint was still very soft so it's probably been leaking very recently.

With that off, bring it indoors so you can clean it up and rebuild in an environment where you're less likely to loose small components.  Marvel at the sludge that oozes out of the reservoir.

Then, learn that you need a pair of circlip pliers to remove the circlip so that you can clean and rebuild the master cylinder.  Find out you don't actually own a pair, and that nowhere local that's open appears to carry them in stock, and end up ordering some online to be delivered in the next few days.  Nothing else for it but to remove the several layers of paint and get the cylinder cleaned up as much as possible.

So yeah.  That's it.  At least I can see the letters on the thing now, I suppose that's something.

[BeEP]

Liked for perseverance, not for having to wait to get it finished!

[danthecapriman]

Frustrating!

At least it’s off and ready to work on now though.

Ive got circlip pliers at home, but typically where I need them most often is at work. It should be up to my employer to buy tools for us to put in our vans but as you can imagine, they rarely do. I’ve taken to using pin nose pliers (modified with a grinder if needed!) or even a pair of old scissors to get circlips off before now. Be careful if you do try this though, especially with scissors!

[Isaac Hunt]

I always clean the bore with some fine wet'n'dry and some wd40.  I get some wooden dowel, wrap it in kitchen roll and masking tape so that when the wet'dry' is wrapped around it, it is a good fit in the bore.  Often they clean up very well.

[Angrydicky]

Those Lockheed tin can master cylinders are nice, simple and reliable.

We use a proper honing tool at work but in the absence of that, wet and dry and WD 40 should do the job once you’ve got it apart. Bore pitting and corrosion is a big no no. Whether it’s got any depends on how well it’s been looked after, if it hasn’t had a fluid change for decades the fluid will have been full of moisture, with predictable results. My Royale master cylinder was in good condition, and only needed a hone and seal kit (it wasn’t leaking) while my Reliant Robin master cylinder (12 years newer) was badly corroded inside and had also been leaking for some time when I bought it. That needed sleeving. Both units had black sludgy old fluid in their reservoirs so I just caught the Royale one in time.

There are only two seals in there. Either a ring seal and a cup seal or two ring seals. If both options are available for that bore size the kit you bought should have come with both. So you might have a seal left over. There may also be a non return valve in the kit. That’s only used for brake master cylinder applications so as this is a clutch you don’t need it.

We can resleeve the master cylinder if required, or even sleeve and rebuild it. Hopefully it won’t come to that but make sure you inspect it thoroughly by shining a light down inside it - new seals aren’t going to make any difference if the bore is corroded.

Only other thing to be aware of with this style is the reservoir can rot out as it’s mild steel with limited protection. Most of the ones we see that are rotten are earlier ones from 1930s-40s-50s cars so hopefully you’ll be ok. It would be wise to paint it to protect it once done.

[phil_lihp]

Good that you have at least found the problem, it's one more thing that will be sorted  and reliable once this is done at least.

[vulgalour]

@Angrydicky It had a fluid change fairly recently and while the fluid did come through clean, I'm guessing the sludge was just trapped in an awkward space inside the reservoir or something.  Until recently, I hadn't had any issues with this so I think it's the period of time its spent sat not doing much that's caused the issue, perhaps a seal had stuck, or there's some very slight surface corrosion that was dislodged when I first used the car again, something like that.  It's one of those cars that seems to have had money spent on it being shiny for shows, but not much spent on the important stuff, it's amazing that I'm still even now working through areas that have been neglected by previous owners.

[vulgalour]

Boring rubbery stuff update since these arrived recently.  I had hoped the circlip pliers would have arrived by now so I could rebuild the cylinder, no such luck yet.  Still, got this relative rarity to chuck in.  It's pretty tired on the other side, clearly this was the drivers side mat for most of its life.  Being a reversible you can just flip it ove and it looks fine in the passenger side.  On the lookout for another one so I have a matching pair in the front.  The only other ones of these I've ever seen are in @phil_lihp's brown wedge.

Also got myself some mudflaps.  Just after getting these I spotted some originals  with Princess branding on over in France, typically, so these will have to do.  They're still Unipart originals so they'll look the part.  They're a really easy thing to fit and should stop the rooster tails up the rear wings and cut down on the spray, making the car a bit more visible.

Profile looks okay, grooved side to the back, by design.  Simply bolt the clamps down to the arch return.

Oh yeah.  Forgot about that.  There mostly is no arch return for two reasons, the first being rust, and the second being that they were rubbing in a couple of spots when the alloys were fitted.  I don't have the welder set up yet, that's been pretty low priority, so these will have to wait until this is fixed properly.

[vulgalour]

Today, the circlip pliers arrived and that meant I could get this clutch master cylinder rebuilt.  First obstacle was filling down the points on the circlip pliers so that they actually fit in the holes of the circlip, this probably took longer than the actual rebuild.  The master cylinder was quite stuck and the seals were less flexible than the new ones so I imagine that was part of the problem.  Very easy to take apart, all the same.

The Copic marker was what I used, wrapped in fine sandpaper, for cleaning the bore.  I couldn't find the wooden dowel I know I've got somewhere, but the fit was close enough once I'd wrapped it.  A bit of WD40 helped lubricate things and that got the minor surface rust off at the pedal end of the bore.  It wasn't that bad and cleaned up fairly fast even with just 2000 grit paper.  It took a little longer to get the gunge out of the other end of the bore, some sort of black rubbery ooze.

Then I just pushed everything back together in order and it was done.  The circlip was a bit fiddly, and the dust boot was a little challenging to stretch into the right place, but other than that it was straightforward.  I also made sure the new seals went in the same way around as the old ones.  The spring was in really good shape and with the exception of the tiny bit of rust stain on the end of the bore, there was no corrosion I could see on any of the parts.

Refitting went surprisingly smoothly, everything just sort of lined up and didn't fight which is not at all what I was expecting.

I found I couldn't bleed this on my own so the other half did pedal duty.  We got it to the point that it was just pushing fluid out after spending quite a while getting all the air out, and while the movement of the clutch arm is improved, it's still not enough.  It seems likely the slave cylinder has failed too.  I've got a new seal kit for the slave as well so I'll rebuild that tomorrow and we'll bleed it all again and hopefully have clutch operation back.  If I'm really unlucky, the clutch hose has also failed, though that seems unlikely since it's not exhibiting any weirdness.

One thing I did find when looking for something else that I didn't think I could get, was the proper shaped conical grommet things for the timing belt cover.  These are part number CAM5969 and normally sold as Mini heater cable grommets.  They just happen to be exactly the right size for what I needed and now the timing belt cover doesn't rattle.

[Stanky]

On 7/19/2020 at 1:50 PM, vulgalour said:

Boring rubbery stuff update since these arrived recently.  I had hoped the circlip pliers would have arrived by now so I could rebuild the cylinder, no such luck yet.  Still, got this relative rarity to chuck in.  It's pretty tired on the other side, clearly this was the drivers side mat for most of its life.  Being a reversible you can just flip it ove and it looks fine in the passenger side.  On the lookout for another one so I have a matching pair in the front.  The only other ones of these I've ever seen are in @phil_lihp's brown wedge.

 

Ooof, those are lovely - I'd never even thought of reversible rubber mats as being a 'thing' but what a brilliant design, doubles the service life of them easily. Is it at all possible to use this one to make a mould from using plaster of paris or something and then a 5l bottle of liquid latex to make a small run of them? Granted it'd only be one-sided but I bet you could make a few and sell them to make it a cost-positive venture?

[vulgalour]

In theory, yes.  Who's going to want to buy them, though?  I think I'm the whole market for them.

[Stanky]

If you tried it out and they came out OK then you'd have your own ones, and a flat-ish mould could be stored somewhere in case anyone ever asked for a set after they saw yours? Might the owners club be interested? I don't mean produce them by the thousand, but at £30 a set you'd probably turn £20 profit for slopping some liquid latex into a mould and leaving it for a week to set?

[Fumbler]

Cracking idea. Seems simple enough to do.

[somewhatfoolish]

Scan it, flip the image then they could probs be made with a 3D printer, squidgy stuff can be printed now.

[vulgalour]

All options for the future, I'm sure.  Not sure I can be arsed, personally.

In other Princess news, it works!  Removed the slave cylinder and found that there was some more of the black gungy deposits inside it.  Also found there was some surface rust on the bore and, right at the end where the piston doesn't quite travel to, some minor pitting.  I cleaned up the bore the same as I did for the master cylinder and got it as clean as I could before refitting a new seal to the piston and the new dust boot.  Top tip, if the piston is stuck inside you can remove the bleed nipple and insert a skinny rod (I used an allen key) to push the piston out, works a treat and doesn't do any harm to anything.  Piston had some of the gooey stuff on the edge which was probably why it was a bit stuck and while the old seal was still quite flexible and appeared fine, I replaced it with new anyway.

Then simply screw the cylinder onto the clutch hose (because it's easier that way), screw the bleed nipple back in hand tight, and put the dust boot onto the push rod rather than the cylinder.  Line up the push rod with the piston, and then the cylinder with the bolt holes and bolt it down.  Ease the dust boot on to the slave cylinder - some I've seen have a metal ring or cable tie to hold the boot in place, most don't, mine never has - and tighten the relevant bits up.  Then spend ages with different pedal techniques to evacuate all the air and that's it, the gears return.

Drove it around the block and it's fine, gear change is as good as I've ever managed to get it, so it's still got that rubber and yet also notchy first gear selection going on and a general vagueness about where the other gears are in relation to the lever, so it'll do.  I also checked the head bolt torques and they're all correct but I'm still getting a very tiny bit of what seems to be totally plain water appearing at the front of the block at the head gasket seam.  Since it's not overheating, mixing fluids, making clouds of steam, or losing coolant I don't really know what's causing this so I'm just going to keep an eye on it for now.  I've bought a replacement head gasket just in case it turns out the one that's fitted is bad.

Anyway, the Princess now seems to work?  Here's hoping it stays that way for a bit.

[vulgalour]

Probably got the slave cylinder seal on the wrong way around so I have to take that all off tomorrow and redo.  Instructions and diagram in the manual aren't clear, like this is one of those things you're just supposed to know so it isn't mentioned.  I just copied what was there when I took it apart so maybe the seal flipped and that was part of the failure.  Whatever the reason, an easy fix.  The diagram also suggests the hose and bleed nipple are in the wrong holes and should be swapped, which they can be since they're the same thread and go to the same place, so I'll do that too and maybe it'll bleed a little easier.

[dozeydustman]

Good to See Princess back to health

[Angrydicky]

The flared side of the seal always faces the fluid source i.e. away from the boot. I think you have got it the wrong way round looking at the pictures. Amazing it's working at al!

That type of seal will never be able to flip in service btw, if it was the wrong way round that'll be a previous owner mistake and possibly the reason for your poor gear engagement.

The notable exception to that rule is the front seal on the secondary piston on a tandem master cylinder is always the "wrong" way round.

[phil_lihp]

Hussah, good to hear it's back on the road!

[vulgalour]

First job today after having had the incorrect seal orientation pointed out was to remove, dismantle, and rebuild the slave cylinder.  A very easy job, happily, and the seal doesn't appear damaged or deformed in any way so I reckon we'll get away with it.

What I hadn't expected was how much it would improve the gear change.  The gear change has always been a bit rubbish in this car, I'd been told they were just like that, and the rubbery and then notchy selection of first has been a feature of this car since I bought it back in 2012.  Because that's how I thought it was supposed to be I just accepted it.  Now, the gear change is much improved, the rubberiness is gone, as is quite a bit of the vagueness.  I was honestly quite surprised and it must have had this seal in the wrong way around for at least as long as I've owned the car, and probably for quite a while before that.  Next, I wanted to take the car for a quick test run, and maybe even an errand if I was feeling confident.  First up was I spotted a minor weep from the mechanical fuel pump blanking plate, this is quite common and usually because one of the bolts isn't quite tight enough.  Wound the bolt in a bit further and... it stripped the thread.  That's not the first time this has happened on this particular bolt and I had already fitted two longer matching bolts to compensate.

Had a rummage and could only find a bolt that was too long and some washers, so I got it together well enough for a test run.

The test run turned into a trundle, the car was behaving really well and I was so impressed with the gear change improvement that it seemed sensible to just get everything done.  Oh yeah, people are staring again, like stopping what they're doing and staring.  How do I forget that keeps happening with this car?  Made it with no bother all the same, the valve train has quietened down a bit too now it's had chance to warm up and cycle the oil about a bit more.  Temperature stayed nice and stable, all the gauges pointed where they should, everything was great.

I was after some bolts to replace that bodged in one, a length of pipe for the BX to test an air leak theory, and some gloves since I ran out today.  Got two out of three, nowhere had any gloves which really shouldn't have been that surprising.  Trundled home and found that the water or whatever it is appearing at the head gasket join is actually coming from the Wellseal used on some of the joints so I assume it's just a component of it that's running off as it gets warm.  Wiped everything clean and it hasn't reappeared in any noticeable amount so that was reassuring too.  Tok out the bodge bolt and washers and replaced it with one of the new ones and that almost went well too.

Mmm, bolt nice and snug... what's that noi-fweeeEEEE*pop*.  Er... what?

There's a bit missing on the casting now.  The bolt holes that go in for the mechanical fuel pump plate are blind ones, they don't go into the engine itself, they're just cast on the top like this.  The end of the bolt that's always caused problems and popped a tiny bit of the end of the casting out.  I could see there was something stuck in the bottom of the bolt hole and with a bit of wire, prodded it out and ended up with a blob of white-ish silicone sealant that was so black on one end there's no reason it was never seen by anyone and removed.  This is an old issue, again predating my ownership of the car, since I've never used this sort of sealant before.  I can only assume the blob of sealant is what kept making the bolt undo itself but now I had a brand new bolt in with a presumably better thread, the sealant couldn't push the bolt and instead pushed on a very thin part of the casting.  There's no cracks or leaks, like I say this is a blind hole that doesn't go through into the engine.  I did have the car running for a while at idle and with fast throttle and nothing was pushed out through this hole so I'm confident I don't need to dismantle things to fix it.

Otherwise, the car has behaved impeccably.  It doesn't run on at all which is a problem it's had before, especially on very hot days like today, it manages to keep at a steady temperature even in traffic, and the brakes inspire confidence even when faced with Southerners suddenly appearing alongside and then cutting in front of you.  It's actually been really nice just to get out in the car, even if only for a handful of miles.  I might even treat it to a wash, it's been so good today.

[spartacus]

That's great news, it good to see something going right for a change, you seemed to be having a run of infuriating niggles with both cars. 

I'm not surprised people stare, I can't remember the last timei saw one of these on the road and I don't ever recall seeing a modified example.

[ETCHY]

Brilliant to see it going well 

[phil_lihp]

Very pleased to hear this is finally sorted and on the road, fingers crossed it rewards your hard work with a bit of reliability now.

[sloth]

id helicoil those 2 fuel pump blank holes. and you can get alloy solder to fill that hole with. nice easy mornings fettling there.

[MikeKnight]

Hooray!

So nice to see this back on the road and behaving. ?

[vulgalour]

Now that we're running again, I can turn my attention back to the cosmetic.  Just ordered some new vinyl for the parcel shelf since the leather that was salvaged off an old sofa has not fared well, shrinking so much it's deforming the parcel shelf board beneath.

I also found some parcel shelf speakers I liked for almost nothing.  I had been looking at the really massive options out there and they didn't feel quite right so I'd held off until these little ones popped up for a tenner recently.  I like that they're a bit smaller, they fill the space well without dominating it.  I also like that they're a matched pair, something that I'd been trying to find with the larger options, many of which were just two speakers the same, rather than mirrored like these.  They have a bolt built in so you can bolt them down to the parcel shelf too, which is an improvement over the smaller PYE parcel shelf speakers (which I still have) that the car came to me with.  Suppose I better make up my mind about head units.

[High Jetter]

They look good, very much in period, but I'd have swapped them over. Not sure why, just the (weird) way I look at things.

[vulgalour]

Been trundling about in the Princess today, trying to get it a bit more on tune.  I had it running far too lean, corrected that and adjusted the idle accordingly.  I'm now presented with a throttle that's sticking open occasionally, raising the idle by about 100rpm or so.  It has done this before when the throttle cable was adjusted too tight, and when it was earthing through the throttle cable because the main earth was bad, this time neither of those things are causing it, it just seems to be a slightly sticky mechanism.

Gave the mechanism a squirt of lubricant which got it to stop sticking almost entirely, it probably just needs me to drive it a bit more to get the thing to free off, it's not sticking so badly the car is running away, and it's not doing it every time I come off the throttle so I don't think it's something to worry about.

As a result of squirting the mech, I also discovered a very minor air leak in the area.  The air leak was probably from the carb spacer since I learned the four nuts holding it down weren't quite as tight as they needed to be.  A repeated squirt didn't improve the revs so maybe that's what it was, maybe  there's a tiny leak at the throttle spindle seal on the carb, I'm not entirely certain.  I'll keep an eye on it for now.

Another thing I noticed is that the side of the gearbox casing that was always a little damp, though the leak was never obvious, is now dry.  Perhaps it's coincidental, or perhaps the slave cylinder seal that I corrected recently was actually letting out a very small amount of fluid for a long time and that's why that area was wet so often.  This discovery also highlighted that the sump gasket is definitely weeping on the front edge, I do have a new gasket ready to go on, and I'll do that when I next do the oil change and I'll take the opportunity to clean out any gunge that might be hiding in the sump.  I've never removed the sump because I wanted to be sure I'd solved all the other leaks (there were so many leaks) first and now I finally feel confident that I can do that when the next oil change is due.