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MG TD TF 1500 - SU Fuel Pump Noisy

On my 53 TD Mk II, one fuel pump is very quiet, while the other (the outboard one) is noisy. Unlike my other MGs, this pump never seems to stop clicking, even when the engine isn't running. Suspecting a leak, I did find gas underneath the internal filter hex plug, so I replaced this plug. I can't find a leak, but the pump clicks even when the engine isn't running, and is noisy enough that I can hear it when the engine is running.

Both pumps were purchased from a reputable rebuilder at Carlisle in May.

Any thoughts?

Ira
Ira Spector

Hi Ira,
I would suspect that the diaphram is punctured or that one of the valves is stuck open or has got some gunk preventing it from closing properly.
The valves are easy enough to check out and should be done first.

Hope this helps,

Paul.
Paul van Gool

Ira

If the pump doesn't stop running,it's not building up any pressure.There is a filter in the inlet side of the pump that may be plugged up,or there may be some dirt under the reed check valves. To get to these items,remove the pump fittings. You can lap the sealing surfaces of the valves with 500 grit wet sand paper and a flat piece tool steel or flat glass.

Regards
Ermit
Ermit Starnes

Don't overlook the possibility that the base of the valve (the one machined into the alloy base) may be pitted. This is common on pumps that have sat unused for long periods. The moisture in the fuel can corrode the base. No amount of lapping the valve disc can cure this.

I rebuild pumps and can highly recommend the rebuild kit that comes from Burlen Fuel Services. I buy mine from Brown & Gammons (slightly cheaper) - about $40.00 including shipping. These kits contail virtually EVERY part that can possibly wear. I've never had a pump fail to work perfectly after installing one of these kits - UNLESS the base valve seat is pitted.

Regards,
Lew Palmer
Lew Palmer

I found a leak in the carbs, at the nut on the bottom. Will try tightening tomorrow. Hopefully this will solve the problem. (These were rebuilt carbs, too!)
Ira Spector

I don't get it. Somethings not right. I thought the pumps were interconnected via the hose between the carbs. If one carb leaks, then BOTH pumps run faster. If the valves wasn't closing on one pump, then the good pump is pumping fuel back into the tank via the interconnecting fuel line. That means the carbs aren't getting enough gas AND the good pump is running faster to keep up with all of the leaks!

From the message "Unlike my other MGs, this pump
never seems to stop clicking, even when the engine isn't running."

That means that the lower valve isn't seating, but the upper one is. The upper valve is good and is keeping the fuel discharged by the good pump from back flowing into the tank. The lower one isn't seating and the pump can't build up pressure. The upper valve seats on a brass insert while the lower one seats on the die cast housing. As Lew says these housings get pitted by water. You can/could buy new housings. I've rebuilt several pumps that way.

Blake
Blake J.

Blake and Lew,

I tightened the nut under the carbs below the adjusting screw (my jargon is probably wrong). the leak got better, and the carbs slowed in ticking, then got worse. I'm going to have the guy who rebuilt the carbs make good (he stands behind his work). Then I'll see if the fuel pumps keep running.
Ira Spector

Blake and Lew,

The bad carb leaks, a very little (just enough to wet my finger when I run it around the bottom of the gasket, but nothing drips), from the main gasket the runs around the base, despite tightening the screws that run around the base. It actually appears to have two gaskets. Since this is a MkII, I disconnected the post wire so that this carb would not run. The car ran fine, for over an hour, with no problems. Having rebuilt the carbs, there are no visible leaks. The other one runs fine, with no clicking after startup. I plan to take the noisy carb off and open it up. There is a ProLine glas gas filter on each fuel line, but the carbs had been run before the tank was cleaned and the filters were added. The pump did run when originally installed; the filter for the bad one appears to be dry. I'm hoping there is dirt stuck in the valves. What should i look for? How can I clear it?

Ira
Ira Spector

This thread was discussed between 19/07/2001 and 09/08/2001

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.