Pressure bleeding in the ghetto...

[johnl]

So, a few weeks ago I tried 'gravity bleeding' the clutch hydraulics as I read somewhere should work, by just opening the valve and letting fluid drain through with gravity. Some fluid came out, and maybe a few bubbles but I can't be sure that this wasn't just air leaking into the bleed tube at the valve. In any case, essentially it didn't work, the fluid does flow through, but the rate is glaciallly slow with this method. On the upside the shift action felt a bit better, so perhaps those bubbles were air from inside the system.

Still not satisfied that I had achieved much (and certainly not a complete fluid change, which was the main point), today I pressure bled the system.

To do this I found a plastic screw-on lid that happened to more or less fit the orifice on the reservior (in this case it was the cap from a Penrite oil bottle). I then made a spigot from an old brake bleeder nipple; silver soldered a flat washer at the top of the thread next to the hex, drilled the centre of the nipple out with a 4mm drill bit and lead soldered a 4mm steel tube into that hole (this tube may not be necessary, you could probably just use the existing shaped nipple end, but I'd already cut that off in my enthusiasm). Then I drilled a 10mm hole in the centre of the plastic cap for the nipple to fit through, and tightened it with a 10mm nut. The soldered on flat washer and the nut hold the nipple in place, and I usd a couple of fibre washers to help seal it. The stock cap I then replaced with this cap now fitted with a tube.

Next I took an old tyre valve, removed the schraeder fitting and burnt the rubber off. This leaves a brass tube to which a tyre pump can be attached. This tube was then inserted into a length of rubber tube, and the other end of the rubber tube fitted over the tube coming out of the reservoir (and tightened with a clamp). Next step was to fit a plastic tube to the slave bleeder nipple, then pressurise the reservoir using the tyre pump, then open the valve at the slave cylinder by pulling it out about 5mm (after removing the little clip).

Next step, watch fluid come out of the valve through the tube with a good strong flow rate, while also keeping an eye on the level in the reservoir. The rate at which the reservoir empties did decrease as the pressure drops, requiring a few pumps on the go to keep the fluid coming. This isn't helped by the cap leaking air (it's not a perfect fit), but it was easy to keep the pressure high enough.

When I had emptied about half the contents of the reservoir through the valve the fluid became a fair bit clearer, but no bubbles. But then, suddenly a whole heap of bubbles, and then no bubbles, at which point I called the job done. I did need to stop once to refill the reservoir, and then top it up at the end.

Is it my imagination, or does the clutch action now feel just a bit lighter? I'm not certain, but I am sure that the gear shift action is now quite noticably lighter than before, and has a more precise and better feel to it. I'm pretty sure the clutch was not previously completely disengaging 100%, and that this was also a bit erratic at times, because on occassion the gear lever would need a hefty pull or push to get it out of a gear (not so much going into a gear, just getting it out of a gear). So far this seems to have stopped happening.

Happy days...

Regards,
John.

[poohbah]

I'm beginning to think that Johnl is a nom de plume for James May!

[bazzbazz]

So which one has more hair?   

[Citroënbender]

Oh my...

[poohbah]

Hey John, hope I didn't offend you. I reckon James May's shows are great: Man Lab, The Reassembler, Cars of the People etc...

[johnl]

The veracity of the comparison eludes me. There might be some similarities, let's see:

Mr May is quite famous, and I'm not...
He is quite wealthy (must be, surely), and I'm not...
He is a multi-instrumentalist, and I'm not...
He has driven a large number of the worlds most desirable cars, and I can only dream...
He still has an enviably full head of hair, and mine has thinned depressingly...
He has built a house out of Lego, and so have I (I was very young and the house was much much smaller than his).

This is not working very well...

Regards,
John.

[johnl]

I just thought some people might be interested to know that pressure bleeding is possible without having to invest any cash in a kosher pressure bleeding kit. And how it might be done. This method could as easily be used to bleed the brakes as the clutch, though the clutch seems to need pressure bleeding while I easily bled my cars' brakes the usual way, with my wife pumping the pedal.

Pressure bleeding would mean that the brakes could be bled as a 'one man' operation, not needing the assistance of one's spouse to operate the pedal (who you will end up having an argument with due to your unreasonable lack of understanding of her understandable lack of understanding of the process...).

So, this information could potentially save your partnership...

Regards,
John.

[Citroënbender]

May embodies the popular myth that UK blokes are still (frequently) white, well-spoken, versed in hand skills and generally all-round decent chaps. It's allied to the same myths that saw their  population vote to leave an economic alliance in their best interests. I wish them all the best in marketing the facelifted Austin Allegro that will surely Make England Great Again.

Meanwhile, Bazz leads the "make it yourself" charge with a pump sprayer converted to pressure bleeder... I have tried myself pressurising via the cap, and found it eminently subjugate beside the pump bottle approach. You can push a lot more fluid through without fear of running "dry". I would be very curious to know if more air again can be extracted from the clutch circuit.

Today I noticed one of the US market pressure bleeders has a ballcock in the supply line. What a great idea, and such a simple mod.

[johnl]

In Mr Mays' defense, it isn't his fault that he embodies this stereotype, and consequently reinforces it it in a potentially unhealthy way for the society of which he is a product. By random chance he is definitely a white male (a sin of which I myself am guilty, so yet another similarity between himself and myself...), is obviously "well-spoken, versed in hand skills", and in all likelihood probably is a "generally all-round decent chap" (assuming no well hidden predeliction for sexual harrassment / molestation etc...). These are things that might not necessarily be attributed to at least one "UK bloke" with whom he has shared a proffessional media partnership...

I don't think that we can single out the Brits for groups of people who habitually and ignorantly vote against their own best interests, class or otherwise. It's very common all over the World...

I'm happy with my ghetto bleeder, it worked excellently, though ready to admit that the 'Bazz Bleeder' may be somewhat superior. At least when I was bleeding the clutch, there was no point at which fluid was being 'consumed' fast enough that it wasn't very easy to keep on top of the fluid level. When bleeding brakes I can imagine the rate of fluid consumption being somewhat faster, requiring somewhat greater vigilance, and somewhat more spritely activity on the part of the operator...

Regards,
John.

[Craig_m67]

I built a one man pressure bleeder with bits from Bunnings and Supercheap for about $25./ (from memory)
Happy to list, show etc... it's not difficult.

I've used it to change the fluid in my 105 Coupe and the Giulietta QV
Seriously, it's not rocket science (leave that to Bazz)

[johnl]

I built a one man pressure bleeder with bits from Bunnings and Supercheap for about $25.

I win, mine cost $0.00 in scrap materials that would otherwise have eventually ended up in the bin! I love making something useful from rubbish...

it's not difficult.

Agreed, mine was easy to make, should have knocked one up a long time ago (though not all reservoir lids will be as easy to substitute with a cap from an empty oil container...).

Regards,
John.