overdrive rebuild

[oxford]

Hi everyone
I am in the process of rebuilding my overdrive and I have a couple of questions:
The accumulator housing is a bit scored and I think it should be replaced. I have the piston with the metal rings which seem to be in good condition. Should I replace just the housing, or both? Or, I am thinking of going to the later rubber o-ring version piston with a new housing. Can anyone comment on that?
Also, what's the wisdom about replacing the accumulator spring. Mine measures about 6 3/8 inch. I don't have the test rig to test pressure and I am wondering if it would be wise to fit a 3/16 washer under the spring to account for any wear that may have taken some length off the spring. I know new ones are available, but I always worry about the quality of replacement parts.
Also, my operating pistons have the steel rings. Again in good condition. Would you advise replacing them?
Thanks
Matthew

 

[57_BN4]

I changed to orings on the apply piston and left the accumulator as-is. Scoring is a relative thing, you really have to polish it first before making an assessment. If you have some red Scotchbrite pad give it a quick rub and see how much of the scoring disappears- most of it should. If there are deep grooves that the rings obviously can't seal then maybe change it. Make sure you pull out the accumulator and change the orings behind it, a pair of external circlip pliers wrapped in a rag work well to pull it out.

Re the spring- shim it until the pressure is to spec. There is a great instruction manual of how to get full pressure on the Buckeye Triumph website. Definitely make yourself a pressure gauge and bench test it using an electric drill on the input shaft. A regular $20 0-600psi hydraulic gauge can be adapted into the top of the plug next to the breather- it is far easier to find out on the bench that you put the pump cam in backwards than once it is in the car.

Andy.

 

[oxford]

thanks Andy
I have the accumulator housing and the piston out. I made a special tool with a rubber wedge and a cone. If you could see me waving my arms around you'd know what I mean.:rolleye: Anyway, it worked a treat! I'll try polishing the housing. What about honing it with a brake cylinder hone?
Matthew

 

[57_BN4]

brake hone is too rough for ali. I reckon the best place for a brake cyl hone is the rubbish bin, but that's just me. 1200 sandpaper and W40 would do or Bunnings sell the Norton brand of Scotchbrite pads. Andy.

 

[oxford]

thanks Andy
I cleaned the housing with some 1200 then 1500 then scotchbrite. Seems to have come up ok. I think I'll go with that. Any ideas on the spring question?
Matthew

 

[andrea]

Hi Mattew
I followed the Triumph site instruction- and I have changed all the springs (included the ball valve springs) that has worked for me, oldest have very different length from the new

 

[BigGreen]

As in A type;
https://www.buckeyetriumphs.org/technical/AOD/AOD1/AOD1.htm

And J type;
https://www.buckeyetriumphs.org/technical/jod/JOD1/JOD1.htm

...scrol down for next part

 

[57_BN4]

The Buckeye Triumph website linked above has everything you need to get full pressure and then some. There are about four things discussed there which reduce pressure, one of which is a lazy spring. You'll more than likely end up with one washer under it as I did.

Replace the check balls but get two of each and use one to whack into the seat with a punch to ensure the seat is the same shape as the ball. Toss the ones you use for this as they'll have a flat spot from the punch. I remade the apply plunger longer than original although I believe washers can be added to the stem of it.

Rather than using an electric motor to spin it for testing you can use an electric drill on the input shaft. I used one of those impact-driver adapters that take a 5/16 hex to 3/8 square drive and then duct taped a 5/8 socket to the input shaft. A 500W drill will get pretty hot after about two minutes but that is long enough to test. You can roll the trans on its side to remove the accumulator cover without draining the oil to add or remove washers.

Couple other things- they show pressing the rear housing bearings in but it is much easier to warm up the ali housing with a propane torch first until it is almost too hot to touch around where the bearing sits then you can just about throw the annulus/bearing in from across the room. Ditto for removing it when you realise you've forgotten the speedo drive bit.

Lastly, after driving my car for about 1000 odd miles now I have noticed a small amount of oil seeps from the brake ring flange. It is the only leak in the transmission unit so when it comes to stripdown (I'm half way through a restoration) in a few months I'm going to see how easy/practical it is to add an oring to each side of the brake ring. The problem is that there are only two bolts either side and in the middle at the bottom is the anchor bracket for the tie rod which stops the engine unit escaping through the radiator. The pull force on the tie rod during hard braking/crashing seems to be enough to open up the un-gasketed flange and let oil out. At least use a high quality sealant (Threebond 1215 etc)

Andy.

 

[oxford]

Thanks everyone
The Buckeye site is brilliant! Andrea, I will take your advice and replace all the springs. The clutch operating springs are different lengths and not within specs anyway. Old age I guess. Andy, I like your advice on the balls. Good idea to buy two for re-seating purposes. The bearings are all good so I don't think I'll remove the annulus. All the shims are fine but I haven't checked any end float yet. No problem with planet gears or sun gear or annulus: almost like new! As is the unidirectional clutch. Not sure what to do about the operating pistons. They are in good condition, and the rings; but new ones with rubber seals are really quite cheap, so I might replace them just to be sure.Thanks for all the advice.
Matthew