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MG Midget and Sprite Technical - Hydraulic hose seals for dummies

At the moment I'm fitting a rebuilt 1360 A series and Type 9 box to my '68 Sprite. I'm using a concentric slave cylinder as per the picture, and I'm having difficulty sealing the hoses.
The cylinder came as a kit (from ebay) with a pair of hoses and a replacement nose piece for the gearbox.
I trial fitted the pieces and decided to swap the feed hose for one with a 90 degree banjo to make a neater run out of the bellhousing. I checked that the banjo bolt didn't bottom out in the cylinder, and used a pair of copper washers for the seals.
I fitted the engine/box assembly and bled the system, but found a leak from around the banjo.
I pulled the motor only and checked for problems but couldn't spot anything obvious. I thought perhaps I was using the wrong technique, so reverted to the fitting style that came with the kit although not the actual hose, since that was for a Ford, and not long enough.
I didn't use a copper washer since the fitting bottomed out in the casting.
I've reinstalled the motor and bled the clutch which seemed to work. But I now have a worse leak even when not under pressure.
I thought that the conical end to the fitting was supposed to seal in the same way as a bleed nipple when its closed. Is that not the case? What method should I be using?

Ta, Mark



M Crossley

Here's a pic of the original style fitting. I don't know its proper name.

M Crossley

Mark, notwithstanding the fitting seeming to bottom out I would use a copper washer on that type, simply because the inner face of the flange fitment is turned shiny metal.

That looks the ideal method to use to make a leak free fitting

If you use a copper washer the seal will be on the flange face rather than an idealised 'taper in a hole' job.

The actual hole face on the turned base fitment, does it have a machined flat to abut against or is it simply a hole into the diameter of the block?

Bill1

Hi Bill,

The sealing face on the concentric body has been machined flat. It appeared to take a copper washer ok when I used the banjo fitting, although the area isn't much larger than the o/d of the washer. I thought that perhaps the banjo was catching on the edge of the spot faced area. Thats why I thought I'd give the other fitting a try.

I'm guessing that if I use the vertical fitting (for want of a better name) I should use a lock nut?
So:-
i) Load the fitting with the nut and washer.
ii) Screw in the fitting and nip it up.
iii)Tighten down the lock nut against the copper washer.

Or do you think I should put the fitting in the lathe and cut down the length until it doesn't bottom? Then I can dispense with the lock nut and just tighten the body of the fitting directly onto the washer?

I'll use another new washer. The thread is 3/8" UNF. I can't get a torque wrench on, but a reasonable lean on a decent standard length 1/2" AF spanner?

Thanks for you help, Mark
M Crossley

Mark,

Are you sure it's 3/8" UNF, I wouldn't have expected that on any modern vehicle component. Maybe M10 x 1 ?.
David Billington

You appear to be using the Burton kit which from memory has metric threads.
Daniel Stapleton

Yes, it is a Burton part number. I did measure at nigh on .375 and 24tpi, but I suppose M10x1.00 is fairly close. I don't remember the fittings binding at all, but it's that sort of help I was hoping for.
I'll summon up the enthusiasm to pull the motor out again, and pay particular attention.
Ta chaps,
Mark
M Crossley

I've just checked the data on the Burtons website. The cylinder is by Titan, and quoted as threaded 3/8" UNF. I'll do a physical check when I've disassembled.

I think this time I'll remove the cylinder from the bellhousing and dress the area surrounding the spot faced part of the body. That way I can do a trial assembly with the 90 degree banjo and inspect the way the copper washers seat as I tighten the banjo bolt.

Unless anyone has any other ideas.

Regards, Mark
M Crossley

Sorry about the duff info/duff memory. From a photo I have of mine I can see I used a copper washer on the top fitting and it looks like I used one on the bottom fitting as well. I have a busy weekend lined up but will try and get to grovel under the car and shine a torch into the bellhousing to see if I did use a copper washer on the bottom fitting.

The neat way to do this job, which I didn't do when I changed the box and bell housing recently. is to drill the bellhousing and fit a bulkhead fitting. Then inside the bellhousing you can have a short hose from the slave to the bulkhead fitting. From the outer side of the bulkhead fitting on the bell housing you can run a hose to wherever you pick up the master line. The idea being that it's easier to cap and plug the hydraulic lines when the engine is removed.
Daniel Stapleton

Forgot the photo.

Daniel Stapleton

Daniel,
Thanks for your help.

It would make sense to use a washer I suppose. I'm getting paranoid about this now though. I'm sure I'm making this much more complicated than it is!. My latest strip down seems to suggest that the washer wasn't sat centrally around the fitting. They appear to be a bit slack on the bore size.

I've come up with two options so far as per the pic below.

i) I've cut down a fitting on the lathe so it definitely doesn't bottom out in the cylinder thread, and I'll use a homemade copper washer that I've punched 3/8" exactly on the fly press. The washer will seal against the body of the fitting.

or ii) I've confirmed that the banjo bolt from my first attempt doesn't bottom out (without any mods) and could try that with two close fitting home made washers.

In either case I'm getting to the point where they will be done up really tight!

Do you think I could pressure test the setup by fastening a jubilee clip around the nose of the cylinder or the input shaft before I install the engine?

Ta, Mark

M Crossley

Mark,

Rather useful having a fly press and punch and die sets isn't it. I had a sheet metal job to do recently and that drove finishing making the bolster and punch holders for the sets I have, so much easier than drilling and makes quick and clean holes. I was fortunate a few years ago to spot an ebay auction for them shortly after they were listed with a buy it know price of £1 a punch and die, one set is 2mm to 35mm in 0.5 mm increments, and the inch set is an assortment of 34 from 3/32" up to 2". I thought about it for a few minutes then bought them as I reckoned I couldn't lose. Normally the sets seem to get snapped up and fed back as individual items. The racing company I worked at for a short while had their fly press almost permanently set up for punching holes.
David Billington

Ours is at work and mainly used for punching for connectors in electrical panels.
It's handy for all sorts. I just need the skills to take advantage!
Mark
M Crossley

This thread was discussed between 15/05/2014 and 18/05/2014

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