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MG MGA - Clutch bleed

I finally got fed up with my clutch problems and replaced the slave cylinder as well as the seals etc. in the master cylinder. While in the MS I put new seals and no return valve on the brake side. I then filled the reservoir with fluid. I was able to bleed all four brakes with no problem. I am unable to get any fluid to the clutch slave at all. I get a very slight movement at the slave when my wife pumps the pedal but evidently it's not getting any fluid down there. Before you ask, I put the "no return valve" on the brake side only. Before I replaced the slave and master seals I had plenty of movement at the slave.

Any ideas?

Joe
Joe Wiley

The clutch IS more difficult to bleed for some reason. I use a suction device to bleed them both now. Before when I had to do it manually I would: Open the bleeder and hold your finger over the hole. Have an assistant pump the pedal slowly and smoothly to avoid aerating the fluid. After 5-6 pumps have them stop and you release the fluid/air with your finger. Repeat until the pressure pushes you finger off like a one way valve, at that point you are almost done. If you still find it impossible to bleed you may have some sticking going on in the master cyl.
Were the seals that you installed the same shape and size as the prior ones? There were different piston/seal parts used aftermarket at one time and they must be replaced as a set. I Barney has pictures. http://mgaguru.com/mgtech/hydraulics/ht113.htm.
He also has bleeding info. http://mgaguru.com/mgtech/hydraulics/ht106.htm
Sometimes new seals in a master cyl are so stiff they don't return properly. In this case a regulated air source providing less than 15 psi into the top of the master cyl will both seat the pistons and seals and allow you to bleed by pressure.
R J Brown

R. J.

Yes they (seals) were identical to the last ones. Moss has that warning about after-market pistons in their catalog. I also lubricated them well with brake fluid before installation. I also tried your suggestion of removing the bleeder and held my finger over the hole. Nothing. I'm now going to Barney's site and see what I come up with.

Thanks

Joe
Joe Wiley

I was having same problem. Some one suggested removing pin from slave cylinder rod . Loosen bleeder at slave cylinder and push rod in all the and tighten bleeder. This removes pocket of air before you start the process. It helps but I did it two or three times before I got all the air out. Ron
C Tarr

I had a similar problem when trying to bleed the clutch. I use Eezibleed, which is mentioned in one of the links RJ gave you. I was able to bleed the clutch in about 5 minutes and saw a lot of air bubble out...

It kind of sucks to buy one to just use once. Maybe someone in your local MG club has one?

Just a thought.

Darian
Darian Henderson

Darian

I'm going to try to find an Eezi-bleed, or one of the other ones mentioned, and try it. Unfortunately we live here in the "sticks" of the Georgia mountains and there's literally no place to buy these things. When the locals hear you have "one of them foriegnie" cars they tell you "they aint got no foriegnie parts". Same for a local MG club. The nearest one is over 100 miles away in Atlanta. It used to be much easier in south Florida but still no crime, conjestion, or high cost of living here. I guess it's a trade off.

I did print out Barney's section on "clutch bleed" and I'll now try to locate one of those devices on line and buy it.

Thanks for the help everyone.

Joe
Joe Wiley

Maybe someone will lend you an Eezibleed, though for the small cost, the return shipping would almost pay for it...
dominic clancy

Hi Joe
Before you spend money try this method:

Remove cap from Master Cylinder
Fill reservoir
Place bleeder tube on clutch slave cylinder
Open bleed screw half turn
Push clutch fork rod into the slave cylinder and let fluid run until there are no bubbles
Tighten bleeder
Let fork go

Works for me - hope it works for you
Cheers
Brian
Brian Woolmer

When I had a similar problem bleeding my clutch after fitting a resleeved master cylinder a couple of years ago, I got lots of advice. The problem is that the clutch side does NOT have a non-return valve, so as you pump the pedal all you do is move a column of fluid up and down the line to the slave.
One sugestion was to do a litle each day, for 3 or 4 days, and eventually gravity wins with the air bubbles coming to the top.
Another sugestion, which I did not try, but supposed to be a "bush" fix, is to run a pipe to the front right brake bleed screw from the slave bleed screw, and open them both up. Then as you pump the clutch pedal, the fluid will go to the brake line and the non-return valve will operate for the clutch line. (This is also a roadside fix if you have to bleed the clutch, so carry the long pipe and some brake fluid with you on long trips).
I also tried pumping fluid up the clutch line using a large syringe pump. It did not help much. In the end, I believe patience won out. By the way, the original workshop manual makes no mention of there being difficulty with bleeding the clutch line. It just says "proceed as you do with the brakes"!
P. Tilbury

UPDATE:

Well I put on a new slave cylinder and went out and bought one of the pumps (Mityvac) that Barney suggested in his article. Then I filled the master with fluid and after attaching the suction side of the pump to the bottom of the clutch line, where it attaches to the slave, I pumped and I pumped and I pumped. Finally, when I was about to say some really bad words, some fluid and air started to come out. I said them anyway and felt better. I pumped (I won't say how much this time) until nothing but clear fluid came out. Oh yes before you ask I refilled the master each time. Then I quickly attached the line to the slave, hoping to not allow any air back in the line. Then the big mistake!!! I attached the suction line from the pump to the slave bleed. I built up pressure from the pump, then opened the bleed inorder to suck out any air that might have gotten in from the quick attachment of the line to the slave. The mistake you ask? Air can seep in around the threads of the bleed and get back in the line. I should have just had my wife pump the clutch instead but didn't.

By this time I was so disgusted I quit and put the car up for the winter.

I'll let you know if I take it on again in the Spring (April). BTW, any suggestions on where to send my Master Cylinder this year for new sleeves if I decide to go that way? The one that's on now looks pretty smooth inside but I just need to spend more money on the car:-)

Joe
Joe Wiley

I have a Mitivac too. Waste of money. The EEzibleed is better and cheaper.
dominic clancy

I agree with Dominic the EZ Bleed is better than the MityVac. This is one of the few cases in life where it is better to blow than to suck.
James Johanski

I spent $6.00 on a small garden sprayer from K Mart. changed the fitting to fit a 5/16 PVC hose. Fill with Brake-Fluid and pump up pressure.press the trigger til;l the hose is completely full and slide it on the clutch bleeder. Open the bleeder and then press the trigger. The pressure in the sprayer will flush the air and fluid back up to the reservoir.Be sure that you have room for thew fluid or be ready to loose paint. It also works well on bleeding brakes and with engine oil will pre-lube the engine filling the pump and filter at the same time.
I have used various forms of this system for 25 years and it works all the time.
Sandy Sanders
Sandy Sanders

Thanks guys

Any comments about Master Cylinder re-sleeving? Apple Hydraulics maybe?
Joe Wiley

I've used Apple and they were great. You have to send your master as a core, before or after you get the replacement resleeved master. He uses stainless steel for the sleeves if I recall correctly.
The instructions that come with the master say you should bench bleed the master - haven't found anyone who has actually done that because of the mess it makes!
You will have to bleed the clutch again so practice those swear words. Peter.
P. Tilbury

Joe
I have recently acquired what appears to be an NOS Lockheed Master Cylinder, the bores are great and I have put a set of new seals in with the intention of punting it on ebay. If you are interesed, drop me a mail.
dominic clancy

Dominic

I can't find your email address.

Joe
Joe Wiley

I to had this problem the soloution is probably simple the bleed nipple is the same thread as the feed pipe if you assemble them the wrong way round you cant bleed the slave reverse the blead an the pipe and bleed as as usual I think its worth a try

David
David swaine

Huh? I'm not sure I follow you. The bleed nipple comes out of the side and the feed line goes in the end of the slave, opposite the piston. It's pretty easy to follow but I admit after almost fifty years of working on these cars I might be loosing it.

What I was saying (I think) is that air seeps in around the threads when backing of the bleed nipple in order to suck the fluid with the pump, therefore, you permit air back in the line.

I think I'll try the suggestion of pumping the fluid in through the Master Cylinder while bleeding the nipple on the slave next time.

It's going to be a long winter while I think this over.

Joe
Joe Wiley

Joe,

I used White Post some years back, they were quick on the resleeve and painted the body in cast iron gray paint. I just had them resleeve the cylinder rather than rebuild it. The parts are readiy available and it is an easy jod to do on the bench. The problem areas known are the seating of the seals on the pistons, the piston clearing the internal ports and the bleeding of the clutch slave.

Chuck
C Schaefer

Thanks Chuck

How do I contact White Post? I've been on Apple's site and they want $90.00 for a resleeve job. My nephew says he has a new Lockeed in his spare parts and I'm trying to get him to double check before I send mine off.

Joe
Joe Wiley

Joe:

Whitepost.com is their site. They do not list prices nor do they list the resleeve-only option. Give them a call and see what thay can do for you. It looks like both Apple and White Post now use brass sleeves. I think when I needed mine, Apple was using stainless steel, although I'm not really sure. Most experience on this site suggests that DOT5 is not recommended for resleeves. I used DOT4 with no problems.


Chuck
C Schaefer

As Sandy says, the reverse bleed system is simple, and fairly quick. I used a Mityvac, in "push" mode, (just reverse a few connections) and attach to the bleed nipple, partly opened. I pumped, the fluid flowed, and a minute later my assistant looking into the master said, "here it comes". I stopped pumping, tightened the bleed nipple, and topped off the Master the rest of the way. Job done, first time, first try!
Thomas Lennon

Sorry not to view the thread for a couple of days to see how you were gettin on. The slave cylinder has a feed in and a bleed nipple they are the same thread so if you rebuild the slave it is possible to connect the fluid pipe on to the hole for the blead nipple.But from what you discribe it sounds you have it the right way round.I managed to connect the pipe into the upper hole and the nipple to the front and could not bleed the clutch for about two months I even purchased a new master cylinder at great expense. The blead nipple need to be above the feed pipe then it works just fine. I know this sound so simple but it got me for weeks I even had a presure feed worked off a tyre valve inserted in the master cylinder cap It still would not work I just had the pipe the wrong way round

I do hope your problem is this simple

Davis
David swaine

This thread was discussed between 14/10/2007 and 30/10/2007

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