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TR2/3/3A My A-Type overdrive rebuild project, some questions

TuffTR250

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I bought an A-Type overdrive of unknown condition with the intent to rebuild it if needed and install it in my TR3. I bench tested it with 100 pounds of air pressure as described at the end of the "Reassembly" section the Buckeye Triumphs article on A-Type overdrives, and it indicated a problem. Therefore, I have started disassembling it. So far it looks pretty good inside.

I most likely will have more questions as I work in it. My question/problem for today is that I can't get the oil pump to pull out of the housing. Per the Buckeye article and Greasy Hands articles, I removed the pump check valve cap, plunger, and ball. I removed the plug and 2 screws at the top of the pump. I screwed a 7/16-20 threaded rod into the top of the oil pump. I put a 2 inch riser on top of the housing and some heavy washers on top of the riser. I screwed the nut down against the washers with a big wrench but I could not get the pump to pull out. I was concerned that I was going to break something since I was turning the very big wrench very hard. Is there some step I missed to get the pump to pull out? Thanks!
Regards, Bob
 

TR3driver

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Sounds right to me, assuming your riser rests against the housing and not the pump flange. Usually I don't take that pump out, unless I think there is a problem with it. But it does take a fair amount of force to move it. Here's a photo of my setup. The iron bar doubles as a pulling surface, and a lever to hold the housing so I can put full force on the wrench.
 
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TuffTR250

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Thanks Randall! The pump looks ok from what I can see. The only reason I was thinking of taking it out is to check the length of the spring as noted in the Buckeye article. Sounds like maybe I should leave it alone.
Regards, Bob
 

CJD

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It does have a check valve ball too. I am sure you can figure out a way to test that in place, though.
 

Jerry

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Every time I looked at the pump of the OD, I wondered why there is metal on metal pumping oil. Seem like a little o ring would really help. One I pulled apart looked good but could not maintain pressure. It did not seem too worn but was. I never figured out a way to test it??
 

CJD

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Every oil pump I have ever dealt with is metal on metal...even the engine pump on our TR's. I think oil is viscous enough to move without extra seals. I can't remember ever seeing an oil pump worn out. They usually fail from taking foreign object damage.
 

TR3driver

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Every time I looked at the pump of the OD, I wondered why there is metal on metal pumping oil. Seem like a little o ring would really help. One I pulled apart looked good but could not maintain pressure. It did not seem too worn but was. I never figured out a way to test it??
Did you try checking the piston & bore for ovality and taper? (just like an engine) I don't know offhand what the measurements should be, but it's not likely to wear evenly.

Also, how did you know the pump was the problem, rather than say, accumulator rings?

Might be amusing to rig up a way to run the pump with the housing apart, so you could see how much oil leaks out. It wouldn't have to turn very fast, and I think for a quick test you could just use the bushing in the housing to locate it on the mainshaft.

One way to help the pump come out easier would be to gently warm the entire housing. The alloy housing will expand faster than the steel pump, so the fit gets looser. You'll still have to use a puller, but it should be easier to pull. You could use a heat lamp or boiling water to warm the housing. Or even just lay an incandescent trouble light on it for a few hours. Get the puller all installed and ready to go first, so you don't have to handle the hot housing as much.
 
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TuffTR250

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The oil pump is only one of several things I plan on checking. A couple of new questions
1) Although the overdrive is a 22/1374 I see that it has rubber "O" ring operating pistons with "E3" stamped on the bottom of them. The "O" rings look pretty good, but since Moss has them for a real cheap price, should I plan on replacing the "O" rings, and what procedure is used for that to ensure I don't scratch the pistons?

2) The accumulator piston has steel rings. None are broken, but each one has a lot of real small, thin, shallow lines all across each ring. There are more lines on the top ring than the others. I also noticed that the gaps at the end of each ring were not evenly spaced around the piston when I removed it. All 4 gaps are within about 1 inch on one side of the piston. When I did the "air injection" test at 100 pounds of air pressure, I heard air flowing out somewhere in the accumulator area but I could not tell if the air was coming from around the piston since the acumulator springs and cover were all installed. Therefore, my question...how do I determine if the accumulator piston is good or not, and what options do I have if the piston/rings is bad?

Thanks for the help!
Regards, Bob
 

TR3driver

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1) The iron rings for the operating pistons have been NLA for a long time, so converting to the O-ring pistons is a common 'fix'. I'd replace them. I use an old dental pick with a curved tip to hook under the O-ring from the side nearest the face (where it doesn't matter if there are a few scratches).

2) If there is visible damage on the face of the rings, I'd replace them. The piston is less critical, some scratches/wear on it won't hurt anything. Unless it's broken, or has damage inside the ring lands, it's probably OK. Check out the bore as well, if it is too bad off you may have to convert to the later piston setup (or replace the housing). In theory, I think it should be possible to make and install a sleeve (that takes the original piston) to save the housing, but I don't know of anyone who does so. Converting to the later setup is easy and cheap.
 
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TuffTR250

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Thanks Randall! I looked at the Moss web site and I could not find that they sell the steel rings for the 1-3/8 accumulator pistons. Is there a source for those?

Also, looking at the Moss web site I could not determine what parts may be required (and available) if I decided to convert to the later accumulator set up. Would that require their new accumulator housing, new piston, new springs and new spacing tube? Thanks!
Regards, Bob
 

TR3driver

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Where did you find an 1-3/8" accumulator? AFAIK there is only 1-1/8" and 1-3/4", at least on Triumph A-types.

TRF has the 1-3/4" accumulator rings listed, PN 500605.
ORS in the UK seems to have them too, for a much lower price (but watch out for shipping costs). https://www.overdrive-repairs.co.uk/buy-spares.php?cat=A Type Spare Parts List

To convert to the later accumulator, I believe you'll need:
518601 spring
501909 piston assembly (includes rings)
501908 housing (not sure if it includes the 501910 O-ring or not)
502563 spacing tube

https://trf.zeni.net/TR6bluebook/index.php?page=96
 

titanic

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Even though TRF lists all of the parts, I would be surprised if they were in stock. Other sources for the parts would be Victoria British, Moss, and Quantum Mechanics. In the UK, Rimmer Brothers is another possibility. The total for the parts from VB comes to about $270+shipping.
I made the change a few months ago and am satisfied with the results.
I believe that 1-3/8" is the dia. of the operating pistons.
Berry
 

TR3driver

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Even though TRF lists all of the parts, I would be surprised if they were in stock.
They've gotten a lot better about that than they used to be. If it says "CUR" in the database, they can usually ship within a week. I've had one or two items that had a problem (like when they found out an entire shipment of trim rings was made wrong and had to wait for a new shipment), but usually the on-line database is accurate.

Rimmers OTOH has shipped me an awful lot of parts that didn't fit right. If I had to order from the UK, I'd much rather do it from the folks at Overdrive Repair Services (the link I gave above). Worth noting that they have a lot of parts that are not listed on the web site, so it's worth asking if you can't find something.
 
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TuffTR250

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Thanks Randall! I was trying to find overdrive parts at TRF looking at TR3 catalog and couldn't find anything. I did not think to look at TR6 catalog. And Berry is right. I had a senior moment, it is the operating pistons that are 1-3/8. I would like to stick with the large accumulator and springs in the 22/1374, so I will probably try for the replacement steel springs. I have read in Greasy Hands article that when they tried to install the accumulator piston with steel rings using a hose clamp to hold the rings, the rings broke. I guess I will need to see if I can find a real small ring compressor.

Today I plan to measure the float on the annulus assembly. I am hoping I don't have to remove that from the rear casing since the bearings seem good. I do have to replace the thrust washer inside the planet carrier assembly. Some of the pieces of the thrust washer were laying inside the annulus and other pieces are missing. I saw in another BCF thread that one of the gears has to be removed from the planet carrier to get the thrust washer in place. I was sure hoping that thrust washer would go in without removing a gear, but I guess no such luck.
Regards, Bob
 

TR3driver

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Thanks Randall! I was trying to find overdrive parts at TRF looking at TR3 catalog and couldn't find anything.
Are you looking at a factory "Spare Parts Catalogue"? TRF has never published a full catalog for the TR3, only their various "most popular parts" catalogs (aka "Glovebox companion"). The SPC has the full listing.
This is still a work in progress, but I won't be able to work on it for several months, so here's what I've got so far
https://drive.google.com/open?id=0B2H2NJt34OffMWQ4N2EzZGQtNjc0Ny00YmE2LWFiN2UtZWYzMjNjNGFiYzY4

I have read in Greasy Hands article that when they tried to install the accumulator piston with steel rings using a hose clamp to hold the rings, the rings broke. I guess I will need to see if I can find a real small ring compressor.
I think if you'll check, that was an operating piston where they broke a ring. With the early accumulator, you should be able to just gently tap it into place, using the same rod that extracted it. Might have to give the rings some encouragement with your fingers; but the bore in the housing is tapered so it acts as a compressor (more or less).

I saw in another BCF thread that one of the gears has to be removed from the planet carrier to get the thrust washer in place. I was sure hoping that thrust washer would go in without removing a gear, but I guess no such luck.
Oddly enough, you don't have to remove a gear if you're working on an AH unit with the taller OD ratio. But unfortunately, with the 22% OD used on TRs, you do.
 

titanic

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Randall-If I need (and can't tolerate a back order) a part from TRF, I would verify that is actually in stock before ordering, regardless of what the online catalog says. I think all OD parts come from ORS, regardless of where they are purchased. I have been satisfied with OD parts from Rimmer, but always afraid I will be hit with the dreaded "customs" fee.
Bob-I would think that the aluminum bore of the accumulator would show more wear than the steel/cast iron rings. Spending $112+for rings might be a crap shoot.
Berry
 
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TuffTR250

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I see your point Berry. Is it possible to hone the accumulator cylinder very lightly to take out scratches (while ensuring that the taper is not ruined) ?
Regards, Bob
 
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TuffTR250

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This afternoon I measured the Annulus end float using the procedure as described in the Buckeye article. It measured exactly .005 inch so I have decided that is just within specification, and the bearings run smooth and quiet so I do not plan to remove the annulus.
Regards, Bob
 

titanic

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Bob-At this point, you might try lightly polishing the bore, if is scored. A pressure gauge and test rig (as described in the Buckeye article) would be very helpful to determine if you have enough pressure. The cost of the new rings could be lost if the pressure isn't restored and the smaller accumulator has to be fitted.
Berry
 

CJD

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I see your point Berry. Is it possible to hone the accumulator cylinder very lightly to take out scratches (while ensuring that the taper is not ruined) ?
Regards, Bob

I used a hone with 600 grit paper over the stones. I then buffed with polishing compound to a mirror finish. The stones would leave too rough of a surface for the rings to seal. Unlike engine rings, there is not enough motion for the rings to "wear in". They have to have a perfectly smooth bore to function.
 
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