MG Sports Cars

Ok I switched to an early pedal box. Got an early dual circuit brake master (the one with the round resovoir that's sort of slanted looking). Also have a Tilton 75 for clutch master... must have missed measured because the resovior on it is hitting the brake master resovior. Anyone know the piston size on the stock MG clutch master used on early cars -- or other clutch masters that'll fit in the early style pedal box with the stock MG brake master?

Rob, as far as I know, all the CLUTCH masters are the same, it was the BRAKE masters that changed. I believe the clutch master bore is 3 /4".

Thanks Jim!

Speaking of brake masters, anyone know which flare type the early style dual circuit (tilted round reservoir) brake master uses?

Bubble type flares Rob. Rob, if I'm not mistaken the remote resevoir kit should fit the type 75 cylinder and get that out of the way easier than finding another master cylinder. Of course the stock B unit would work if you have one handy as well.

Thanks Bill -- bubble flares. With respect to the remote reservoir for the Tilton 75 -- it can be set up that way. The MC even came with the parts to do that. But, I want to keep the reservior neat & over in the pedal box area & there's not much room for it there. I'm going to play around with it to see if there's a way to mount it that'll look good. If not, my 2nd choice will be to do some measurements on the Wilwood MC with integrated reservoir -- like this... it comes in a bunch of bore sizes so if it fits the area & I need to adjust the pedal feel I'll have more options than if I go with the MG clutch master. Oh, & it's less expensive than either the Tilton or the MG one too.

Rob,
The earliest MGB's used a clutch master cylinder with the reservoir can straight up, when the dual circuit brake master cylinder appeared the clutch master cylinder "can" was tilted toward the fender a little bit to provide more room for the wider brake master cylinder reservoir. Girling masters will work and are available with integral and remote reservoirs in .625, .7, and .75 inch sizes. They have close to the correct bolt pattern as I recall.

Ok Been out of the loop for a while but I`m ready to get back at it. (god willing)
I`m having a bit of a time with the whole clutch thing so I thought I mite go with a hydraulic throw out bearing.
My question is What should I use for a master cylinder?
I`m using a 2.8 with a t-5 tranny and the stock master cylinder just does not seen to have enough "stuff " to engage the throw out.I shortened the throw out arm,used a slave from a 1500 and everything you did Bill but I still cant get the bearing to engage enough.
Just think that this will save me a lot of trouble.
Any advice or suggestions ?

Hi Mike, good to hear from you again. From what I've seen and read almost all use a 3/4" bore master cylinder on the clutch with a HTOB or most British type slave cyinders. Give Brian McCollough a call and see what he recommends. I'm pretty sure the HTOB he uses will work with a stock master cylinder and from what I've been able to find out the bore on the B or Midget is the same, should work with yours.
As to your problems of not getting enough release action, that's one I can't figure out. I remember the photos you posted at one time for your mods and from what I saw it should have worked. About the only thing I can think of would be that the push rod is a bit on the short side and not giving you all the available stroke in the slave cyinder to work with.

I just spoke to Tilton yesterday. I also can't disengage their hydraulic throw-out. They say I need a 7/8" bore. I ordered the Wilwood. Maybe 3/4" will work for you but I don't know.



Edited 1 time(s). Last edit at 05/13/2010 03:51PM by motek.

I used the standard Clutch Master Cylinder from my 79 B, with the HTOB I got from D&D - McLeod, I believe. T5 Camaro tranny with Chevy Clutch. After I got the HTOB correctly adjusted, no problems.

I second Don's comment. When I had the Olds 215/T5 and a Mcleod HTOB from D&D, it adjusted and operated fine with the std 3/4" bore MGB MC.

That's what I have used since '01, stock MGB master cylinder & Mcleod HTOB.

Sounds like 3/4" works on the Mcleod. My stock Triumph bore is smaller.

Rob, the stock cyl. worked great on my HTOB, but the effort was excessive. I changed to the Tilton 5/8" and everything still works great, The key is setting up the Brg. at installation. There is a Tool to use for this purpose. some do not use it and do the measurements manually. Speedway Motors has this tool listed.



Edited 1 time(s). Last edit at 05/16/2010 03:47PM by kstevusa.

What's Brg Kelly?

I have the Mcleod-Weber brg. I purchased from D&D at V8 meet in 2003 in Townsend Tn. It was just weber then, but Mcleod bought them out and is now joint named.

Rob, I think that brg. is just Tennessee shorthand for bearing.

got it. I'm not suing a HTOB... I copied either Graham or Joe Schaefer using a Toyota truck slave. No info came with my clutch but I've read the throw out bearing is supposed to ride on the pressure plate. I couldn't find anything saying how much so right now I have it with "moderate" pressure -- basically the pressure exerted by the spring in the clutch slave. Once I fix the water pump leak & get the car idling smoothly, filling/bleeding the clutch is next.

Rob, I guess it was common knowledge for so long that it's been lost to the world ;-) but in the case of roller type TOB's (throwout bearings) best practice is to hold the bearing just off the pressure plate fingers on release. They do wear and there's no point in encouraging them. With mechanical linkages it was easy, as the return spring would retract the TOB. (If you left the return spring off you might soon be replacing the TOB.) With external hydraulics, a return spring, judicious adjustment, and sometimes a stop was used. With HTOB's the manufacturers rely on such esoteric forces as seal memory and the irregularities of the pressure plate fingers to establish a running clearance much like with a disc brake. It seems to work but probably as much because of improved quality in the bearings as anything. Carbon TOB's as originally installed in the MGB are a different animal and are apparently designed to run with slight pressure against the mating flange.

JB

If Rob is using a std Ford TOB (as used typically in a Fox body Mustang, eg), these are a "constant motion" type and are designed to be in direct contact with the clutch diaphragm fingers....in other words, the TOB has a slight preload on the fingers and is in constant rotation.
I found reference once, that the engagement force was something on the order of 4 lb.