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MG TD TF 1500 - Water pump 2

New MG law states "Murphy was an optimist".
Replaced water pump (pulley wobble) on my 54 TF a few years back (new Moss pump) but kept original pulley. The fit was quite good. Old pulley fit was much better than new pulley for some reason (??). The archives say send it out for rebuild. But time and money (I'm 60 miles from Moss in VA.I was careful to follow instructions etc. All went well.
Now the wobble is back. I keep the fan belt quite loose about 1" plus play.
Archives talk about a lot of stuff. But what is the cause? Shaft wear? Pulley wear (shaft material is harder than pulley)? Bearings?
The hold down nut was loose. Tightening helped some but there was still a slight wobble.

Is this a recurring problem no matter what I do today? Should the nut be torqued on a regular basis?

I'm a bit old for this. Kind of like sticking your hand into a sack of angry tom cats.



Peter Dahlquist

The problem is that both the shaft and the pulley used a straight bore, so after time, especially with a loose nut, the pulley bore wears and a loose fit results.
The remedy is to fit a tapered shaft with a corresponding tapered bore in the pulley. I believe this is the method Butch Taras uses to repair water pumps. He frequents this forum and so will likely respond to this posting.
Lew Palmer

Hello Peter and Lew. The tapered shaft was designed by Phil Marino. It has no way to locate forward and back movement. What I do is machine a taper into the pulley and make a matching tapered collet to fit on the shaft. That way as you tighten down the pulley the collet grips the shaft. This way you can change the pulley to another pump if needed, which you couldn't do with phil's design.

Butch
R Taras

You also cannot ignore the fact that the pumps supplied today were made in China, by the lowest-priced contractor.

Having Butch rebuild an original pump, tapering the shaft and pulley, are the best steps to take. I carry a Taras rebuilt and water pump with tapered pulley fitted in the tool box, and have never needed them!

Tom Lange
MGT Repair
t lange

Butch. As per our discussion on the phone several weeks ago regarding sending you A half dozen pumps after GOFWEST. Am I to understand now that I need to send pulleyís with them as well to be converted for the collets? I was going to send you just the pump cores. Not knowing the internal differences between the originals and repops, are you able to correct the repops as well? I just bought a new pulley and another repop to replace mine in TD-4834 for the trip to Prescott as a temporary fix. I donít like the fiber lock nuts supplied with the Moss pumps. I suspect that the prematurely failures are caused by the nut backing off. Iím contemplating using a thread locking compound to attempt to keep the nut tight. Itís a very pour design feature.

Bill Chasser
TD-4834
W A Chasser

What is frustrating is it is designed to fail.

Is there a pump made that has a positive stop for the pulley on the shaft?

Tapering, needs to be match machined. Near perfect tapering to stop the pulley in the correct location. No room for error?
Peter Dahlquist

The engine builder for my TF-1500 (and TF owner and racer in vintage races) specified this pump from NTG Motor Services Ltd:

Water Pump-Heavy Duty B023HD
http://www.mgbits.com/contents/en-uk/p7992_Water-Pump-Heavy-Duty.html

Information on the NTG website: (Hope my builder read this!)

This new heavy duty water pump has sealed "Lubed for life" bearings and therefore does not need any further lubrication. However, for the sake of originality there is a grease fitting on raised section of the housing

Important:

The seal in the new water pump is a graphite ring that is pressed up against a metal sealing surface, a type of seal commonly found in fluid pumps. To be effective, the pump needs to be spun dry so that the seal will mate properly with the hard surface it is pressed against.

To bed the seal, spin the pump for 60 seconds with a 3/4" drill with the chuck tightened onto the shaft. If you skip this step and install the pump you will almost certainly find a trickle of fluid coming out of the weep hole on the underside of the pump housing if not immediately, within a few hours of installation. Once the leak starts, the pump will have to be replaced!
LM Cook

Hi Bill. It depends on the repop. I had one that I couldn't get to the bearings. It was like they cast the center section of the pump solid and bored it for the shaft. I could feel the bearings but couldn't get to them. Most of the repops the castings are like the original but some have shafts like original, some have a circlip at the top to locate the shaft.


So the answer is yes I can do most of them. If the pulley is loose on the shaft then I need the pulley. The pulley with collet then can be used on any standard pump shaft.
I have been using the nylon lock nuts but am thinking about drilling the shafts I make to take the cotter pin and using castle nuts.

Butch
R Taras

Butch I just pulled my current Moss pump off of TD-4834. The shaft doesnít deflect but as typical the fiber nut had backed off allowing the pulley to wobble. The bearing has a rough spot. Thatíll make another pump and pulley Iíll send to you. After GOFWest. I have another new Moss pump and pulley to install in the meantime for the trip.

Bill Chasser
TD-4834

W A Chasser

Butch I would like to get your contact information to send you a pump to rebuild. Thanks,

Rich
Rich King TD 8732

Hello Rich. Contact me by the email above.

Butch
R Taras

Been thru the archives and can't find the thread size of the water pump spindle.
I want to replace the nut. Seems my problem was the nut worked loose. Can someone give me the size?
Peter Dahlquist

Hello Peter 8mm x 1.0 castle nut

Butch
R Taras

I just went through this on my TD. I had bought a County Brand pulley from British Parts Northwest. The pulley was incorrectly machined on the backside and wouldnít allow the pulley seat. In fact it sat 3/8Ē proud of where it should have been. So I reused my old pulley and pump using Loctite on the nut when it was re-torqued. Iíll see how it holds up for the next few weeks.

Bill Chasser
TD-4834
W A Chasser

I have a Moss pump about 4 years old and the thread is 5/16-24 fine.
Peter Dahlquist

Hello Peter The original pump has a shaft thread of 8mm x 1.0 The after market pumps use a 5/16-24 Both are fine threads.

Butch
R Taras

Thanks fortunately both were available 15 minute drive.
Peter Dahlquist

Shim or new pulley?

Finally extracted the water pump. It is a Moss pump 3/4 years old. There is a shoulder on the shaft stands 0.020 proud of the bearing. The shaft is 0.730 long from this shoulder.
The pulley (original to the engine) ID length is 0.731 from mating surface to the flat. Pretty much line on line.
No ability to really tighten the nut to capture the pulley to the pump shaft shoulder. Guess that's why the nyloc nut.
The wobble did diminish when I tightened the nut but did not go away.

If I shim under the pulley that would mechanically fix the wobble. For how long?

Also the center of the belt is not in line with the shaft/pulley. Off set loads. Could exacerbate the problem.



Peter Dahlquist

Hello Peter. There is suppose to be a .040 thick dished washer between the bearing and the pulley.

Butch
R Taras

Ah there is the problem
Peter Dahlquist

This thread was discussed between 30/07/2019 and 08/08/2019

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