Hi,

I am currently rebuilding the gearbox (4 synchro) and overdrive unit on my MKII 3.8. One thing members may be able to help me with is the method for installing the accumulator piston into its cylinder. Access is very tight and I have been unable to work out a method for compressing the rings. I'm sure there is some sort of Churchill tool for this, but I certainly can't get access to one. How have other gotten around this problem?

Cheers
Terry

 

Welcome to the forum Terry,

I've copied the overdrive question from your Intro for advice from members with the same model.

Graham

 

Taken from the workshop manual, looks like no special tool required, I'm sure its not this straight forward, but I haven't done this job so no experience.


Accumulator piston and spring - removal and refitting

1 For "A" Type units, first refer to Section 16 end follow the instructions covering the
removal of the solenoid bracket paying particular attention to paragraph 10.
2 Now refer to Fig.6.28 and 6.30 and remove the components of the accumulator piston assembly applicable to your car.
3 Withdraw the piston housing assembly end then separate the piston from the piston housing.
4 Refitting is the reverse of the above procedure but it is important to note that correct fitting of the piston rings is essential to the correct operation of the
unit. Make sure that the rings are not gummed up and do not have excessive clearance in the grooves. The "0" sealing rings should be renewed.

5 The accumulator fitted to JCN units is held in position by a large nut at the bottom of the unit. Unscrew the nut and you will find that the length
of its thread is such that all tension on the accumulator spring is relieved before the nut is clear of the casing.
6 Take out the spring, the support pin and the washer.
7 The accumulator piston can be removed by hooking a piece of stiff wire in the groove machined inside the bore.
8 Refitting is the reverse of the above sequence for removal but here also, make sure that the piston rings are in good condition.

 

Thanks John. I have now completed reassembly of the overdrive unit, but it's not yet back in the car, so I won't know whether I have been successful with the fix for another couple of weeks. I'll be sure to let you know.

Cheers
Terry