Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Hydraulic fluid for clutch

I am installing a new master cylinder for my "5-speeder". If anyone knows of the proper technique for bleeding the system, and also the type of hydraulic fluid to use, I would greatly appreciate your input.

Best,

Tom

Same fluid as the brakes, in fact same reservoir unless you have an early machine with the three separate reservoirs. The bleed fitting is under the oil tank, in a black plastic "L" fitting on top of the gearbox unless you have one of the few with an external slave cylinder which is on the lower left of the gearbox.

I removed the coil to make bleeding easier, but it's probably not essential to do so.

Nothing special about the bleed process-just like brakes. Two people with one running the pedal, or 1 person with a vacuum bleeder. Because the master is below the slave, it bleeds pretty easily.

Are you sure the issue is your master?

Steve: Thank you for the timely information. (All I had to do was go to the owner's manual to get the type of hydraulic fluid, duh). However, the info on bleeding the system is appreciated. I am praying that the problem is with the master cylinder, as the thought of removing the engine to get to the slave cylinder is not a pleasant one.

Regards,

Tom

If you are just having clutch hydraulic issues, you might try a comprehensive bleed first to see if that will help. Clutches should be bled at least every two years just like brakes to keep the fluid fresh and moisture free. But most people forget to do the brakes, let alone the clutch.

I keep service notes so I can stay on track, otherwise I'd be years behind like everyone else.

A little past midnight here. I just finished installing the new master cylinder, and am pleased to report that it is functioning well. Removal of the old cylinder was a bit involved; especially the disassembly from the pedal structure. That required some articulated ratchet wrenches and one box-end that I modified with the acetylene "hot wrench" to fit the lower nut and bolt that secures the master cylinder to the pedal assembly.
As I was working solo, I circumvented the bleeding process by filling the master cylinder with DOT 4 fluid with a 27 gauge spinal anesthesia needle, and a 10cc glass syringe. In order to avoid emptying the main reservoir when I removed the feed tube, I clamped it with special vascular clamps used in open heart surgery. They occlude the vessel, but do not lacerate it.
Reassembly was essentially the reverse of the above, with the "fiddliness" attending the installation of the nuts and bolts in a relatively tight area. Dismounting the pedal assembly from the floor helped.
I noted with some alarm that the clevis bolt that secures the fork of the actuating rod to the clutch pedal is wearing notably where it interacts with the pedal vertical member. The Clevis does not rotate in the pedal arm, and wears notably where it inserts into the arm. I was puzzled as to why a rod-end bearing was not used in this application, but I suppose it may have something to do with cost. I will be designing a rod-end bearing modification for the clutch and brake applications, and would advise the forum members to be sure that those areas are lubricated frequently. I have a difficult time posting pictures here, but will try to load one of the worn Clevis pin.
Steve, thank you again, and I add that I was mighty relieved that I didn't have to go after the slave cylinder.

Well done Piloto. As you say, you are lucky that it was the master and not the slave at fault.

Are you in the Morgan Three Wheeler Club? If so, you would have seen my article in the September issue. I'll leave it here because it may be of some assistance next time!

i saw that article and just one more repair I dread. Hopefully piloto took pictures

The whole arrangement smacks of Rube Goldberg. If I ever need to go after the slave cylinder, I will install an external one by making room for it with the "hot wrench".

My thought exactly.

Bunny: Great article, thank you. I drove the 3W for an hour this morning, and the clutch action is excellent. I will join the MTWC forthwith.

Tom