Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Bleeding clutch

In order to install a new brake master cylinder the entire box assembly including clutch cylinder must be removed. After reassembling everything I then began bleeding the system. The stream from the clutch bleeder indicated there were no air bubbles and should activate the rod in the slave but the rod would not move. I was finally able to get the rod to move by using a screw driver as a lever and pulling back while the pedal was pumped. I ran out of time and have not driven the car yet but the pedal feels normal.

My question is can anyone explain why this could have happened? Other than opening the clutch bleeder to empty the master I did not do any other work in that area.

I cannot explain what happened but you need to check the clutch slave cylinder push rod for around 3/8" movement when you push the clutch to the floor. If it doesn't you still have problems. Clutch hydraulics can be difficult to bleed. Usually opening the bleeder and pushing the slave push rod/piston toward the front of the car works for me.

Clifton Gordon

Just drove the B everything feels fine. Anyway, for those of you who experience the same problem just manually lever the rod as Clifton suggested and I did.

It can be hard to get any trapped air up over the bend in the pipe from the clutch cylinder. Some posters have recommended reverse bleeding the clutch system by connecting a front brake caliper bleed screw to the clutch slave cylinder bleed screw, opening both, and pumping the brake pedal. I can't attest to the efficacy of this approach since since the PO had installed silicon fluid in the brake system whilst the clutch still has conventional fluid.

BJ Quartermaine

I sympathise with your predicament, the title of this thread probably being more descriptive than you intended. Having read of the problems of clutch bleeding many times when I had to do mine I didn't even try, I simply filled the system from the slave nipple using a gunson's EeziBleed on very low pressure, which didn't need any bleeding at all. Subsequently I had to bleed a system for someone else and no amount of pedal pumping got anything out of the open slave nipple although there was much gurgling. I then used plan B and siphoned some fluid out of the clutch master to prevent overflows, connected the clutch slave nipple to the right-hand brake nipple (they are the same size) and opened both, then used the brake pedal to reverse-bleed the clutch system. It was equally effective, the brake system needing almost no topping-up afterwards (but it was the large, translucent, dual system reservoir), and took less time and was easier than plan A.
Paul Hunt 2

BTW, you are looking for 1/2" to 5/8" travel of the slave push-rod, if you are getting that and the clutch still isn't working properly then something else is wrong.
Paul Hunt 2

That is a great idea, using the brakes to bleed the clutch. Will have to try it next time. Thanks.


This thread was discussed between 22/11/2007 and 24/11/2007

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.