There is a difference internally between early and late pumps in the outlet valve. Early ones use a brass disk and later ones use a reed valve. Rebuild kits are geared to the later form which include the (expensive looking) brass valve cage, but you can keep the earlier form as it does not wear out. Removing the valve cages can be difficult if not impossible, I made a key to do this.
Screws are all BA.
Coil housing is painted black, but machined surfaces are not painted as far as I can tell - e.g. the outside and bottom of the flange. Pump body is unpainted.
I left out the brass mesh filters as I have had problems with ethanol fuel gunking them up in my fuel tank pickups. I have installed inline filters before the pumps.
I have several old pumps in a box, but I am hesitant to rebuild them because I question the condition of the coils. Are they prone to fail or are they a part that rarely fails?
Cliff
Thank you all for your input. I will ask more questions, Iām sure, as I open it up.
Cliff, the coil test is pretty binary. I powered my coil then inserted the shank of a screwdriver in the middle, where the plunger shaft would be. If you feel the magnetism then the coil is good.
Hereās mine. This is all the photo I have at the moment.
Iāve had a couple where the wire was broken off too short and I had to press the coil out of the body so I could solder on a 2 inch extension wire and then put it back in. If you donāt try to unwrap the paper on the coil you should be ok.
Here are the brass disc valves #7 in an LCS pump.
Here is a reed valve #4 in a later round body pump.
Thanks guys for the input. I think that I will dig into them and see what condition they are in. It seems that a rebuild would be considerably cheaper than buying a new pump.
Cliff
Hello.
I am in the process of rebuilding a SU pump. Is there any info on the coil? I have many many documents on many pumps but NOTHING relative to coil testing, performance, resistance; I donāt know as I am not electrical but there should be something right?! Is the coil performance the same forever?? There must be some degradation over the years, I would think.
I ask this as I have previously rebuilt a SU pump and it works fine on the bench; pumps a few times in the car and stops. (No, not at pressure yet.) Readjust etc, double check the measurements, on and on and still the pump works fine on the bench, pumps a few in the car, which is why I am questioning the coil. Like the coil is just not putting out (pulling in) as factory spec would.
Long story short. I would like to test the coils. How do I do this? And what are the factory specs to compare my test figures to?
I would check each wire if there is a short to ground.
But first there is another trick I learned not long ago.
I had a freshly rebuilt L type pump fail after about an hour drive. It is located under the bonnet on my '38 SS, where it can get rather warm. When it cooled off it worked again.
The SU bulletins say that you should screw in the diaphragm until the points just barely throw over. Then back off to the next screw hole. Then back off four more screw holes. No need to stretch the diaphragm, just put it together.
It was that last bit about the four more screw holes that I had failed to do. After doing that the pump has been working fine.
I have set my XK120 project aside since April, cause of a (dreaded) home remodel project, but hopefully next week I can pick up where I left offā¦ the fuel pump. If you energize the naked coil and then slide a rod, like the shank of a screwdriver in the middle, you would feel the magnetism, which would suggest that the coil works. Then you might go as far as tapping it with a hammer while itās gripping onto the screwdriver shank to see if there is any interruption in the power flow.
If your pump is correctly adjusted, the problem could be blocked fuel pipes. Thes will stop the pump running. In my case I had the the pickup and line from the tank totally gunked up, it took a lot of work to clean out. I put this down to ethanol in the fuel.
Time to blow/suck on the pipes!
I can go measure coil resistance if you want. Cant remember seeing a figure for them. Apart from that, make sure points are clean and the adjustments of points are as per instructions, by bending the fingers.
Hello, I am trying to buy a rebuild kit for a square-body XK120 fuel pump. I looked at Moss Motors and Welsh Jaguar sites. There is a great price difference between the two, so I thought I would ask if anyone has gotten the Welsh kit and was it satisfactory. For the price, the Moss kit does not even include the filter. Thank you.
The Moss kit appears to include everything you could possibly need except the brass sleeve filter.
The Welsh kit has no picture, and Mnt/ could very well mean it is only the mounting parts?
Iāve never bought kits, just bought individual parts as needed from Moss and also SU Rebuilders in San Diego.
BTW Iāve recently learned, through making a mistake, that it is very important to follow the SU instructions when setting the throw-over.
Screw in the diaphragm until the points just barely throw over, then back off to the next hole, then back off 4 more holes. aua_229 Type LCS Disassembly Reassembly.pdf (547.0 KB)
Thanks Rob and Clive, and thanks for the links. I am happy to say that the pump I had gotten back in April from Australia came apart without any mishap. I soaked it overnight and bead blasted the aluminum casing pieces and the coil. I think I can revive the brass filter; aside from being badly scaled, it is very whole and undamaged. To answer your question, this pump has disk valves and there is no resistor. Will post picture once I get the parts.
Question, this is the Moss kit, but it shows only one disk. Am I missing something?
Canāt remember about the second valve, but coming from Burlen I would trust the kit is complete as required. You can probably resuse your current one if needed.
Hi Rob, that square body diagram in your April 22 postā¦ can you post the diagram in its entirety? The parts blow-up that Clive posted shows parts that I did not find in my pump (circled in red). My pump is a lot closer to the one in your diagram. Iām trying to understand if I am missing parts. Thanks.
That coil spring fits under the valve disc. Early pumps didnāt have them. The pumps on my Mk9 donāt.
Not sure about the rest.
Iāve a Burlen service catalogue in the garage, Iāll take a look later and report back.
