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MG MGB Technical - Reverse bleeding

I've read a number of comments on "reverse bleeding " of the clutch hydraulic system from the slave up to the MC. I've searched the archives looking for a description of this method, but didn't have any luck.
Can anyone out there tell me where to find this description, or provide the details of the method?

Thanks a lot.

JR
JR

You'll need an item called or similar to a "gunson's Easy Bleed" which uses air pressure to shoot fluid into the system. Try to have the Clutch MC reservoir as empty as possible. Connect the outlet tube of the easy bleed to the bleeder on the clutch slave. Apply air pressure from a low pressure source (partially deflated tire, etc) The fluid fro mthe easy bleed will push its way into the slave, fill it, and then the fluid continues up through the lines, pushing all the air out ahead of it until it reaches the reservoir and fills it up.
william fox

This is the only way I have done it having read of other difficulties. I pumped *all* the existing fluid out through the slave nipple, and got some right crap out of it too. With my Gunsons kit there was an extra length of tubing that was just the right size to fit over the short pipe that is in the cap that would normally go on the master cylinder, and the other end goes on the slave nipple. Because this was only pushed on I deflated my spare to about 5 or 6 psi as I didn't want to blow this tube off and spray brake fluid everwhere. Then it was just a matter of peering in the top of the master cylinder till clear golden liquid rose above the level of the piston. Disconnected the Gunsons and topped off as normal. Took me a couple of minutes, and when I checked I had full slave travel typically 1/2" to 5/8".
Paul Hunt

JR,
A simple way to do this (and requires nothing extra) is to pump fluid through the slave, then close off the bleader. Let thing settle for a moment (important) and then push the slave piston back till it bottoms out. This will burp any air back through the master cyl. I've been using this method on various models for years and it works very well on the B because of the volume of fluid in the slave.

Kelly
Kelly Combes

Hi,
The easiest way to bleed any hydraulic line on the MG is to take a small container and fill it half full of new fluid, put a tight fitting hose on the bleeder nipple and the other end into the small container of fluid, open the bleeder nipple, and pump the appropriate pedal. The fluid in the line will go into the container on the "push stroke" and the fluid in the container will stop any air from reentering the system on the "up stroke" Keep pumping until there are no air bubbles appearing in the container fluid. Keep the resevoir (sp?) full . I have used this system for years. Its an easy way for one person to bleed brakes or clutch cylinder. A glass container works best so you can see when the air bubbles in the container stop appearing. I threw all of the other ez bleeds etc in the trash years ago. FWIW Alan
Alan

Alan has described the "textbook " method of bleeding auto hydraulic systems, and it has worked well for me for any car EXCEPT the LHD MGB clutch system. With that very circuitous route the line has to take, transversely and vertically, and especially that last little bend before the banjo,that invites bubble capture, Paul's system, or any variety of it, is far more sure/simple. I could not find a Gunsen's when i needed one, so i bought a large pumper style oil can and connected it via some tight fitting hose to the bleed screw and got a bubble free system first time, after messing about with bench bleeding, the "text book" method and some of the most foul, abusive language I have heard in a long time. My 2c CDN worth.
Ken R
Ken Rich

Ken,

I have a LHD MGB (I live in the USA ) and this system has worked very well for me all of the 13 years that I have had the "B" Many engine removals and installs, many brake jobs and the bleeding required. It is just straight physics, bend or no bends you are dealing with hydraulic pressure not gravity. Sure there are other ways to bleed the systems if you want to have all of the toys/tools. But for economy, and in a pinch, the "jar" has always worked no matter what side of the road you prefer to drive on. Alan
Alan

I have always found my simple method to work on MGB clutchs.

Fill master cylinder and open slave bleed valve till fluid drips out. Close bleed valve. Pump pedal up and down vigorously for a minute, rest a minute and pump pedal vigorously again for a few seconds.

Late midget clutchs are more of a problem due to the large bore plastic pipe but the same method works with one minor amendment - on the last pump push the pedal down and hold it for half a minute to let the last air bubbles collect into one at the top of the pipe on the bulkhead, then let the pedal up quickly and that last bubble gets sucked into the master cylinder.
Chris Betson

This thread was discussed between 05/09/2002 and 06/09/2002

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