Sunday, July 26, 2009

Feeling righteous

Sunday was the day for Lucas PI remanufacturing. Over the last few months I've been doing some leg work to acquire the right bits and pieces to recondition a pump or two. I've been finding spares all over the place, at last count I was up to something like 7 pumps in my possession plus the one running on the car!

I've tested a few and many were crap - looking decent and serviceable on the outside doesn't mean they're any good at all on the inside. They all run and pump but a leak shaft seal (drips out of the tell tale) means they are useless unless worked on.

My new best mate, the friendly chappy at the local hydraulics place has been a real help - he sourced the big "O" rings that sit between the pump and the motor. It's the same ones in between the layers of the pump body. He also sourced the "O" rings for reconditioning Lucas injectors as I have run out of original Lucas ones. Trouble is, I had to have 50 - well guess who'll be buying up spare injectors and reconditioning them to make some money back?

The pump seals came from Canleys as did a set of brushes - these are the same as wiper motor brushes, same backplate but the wiper uses 3 brushes and the pump motor uses 2 - you can leave one in situ unused or take it off.

Most of the brushes in the pumps I've dismantled are OK, lots of life left in them but I thought I'd have a spare set in case I needed them.

The ultra sonic cleaner has been good, really gets the fine crap off - it's not as good as I'd like but I think I need to get better at rough cleaning first then use the ultrasonic to ensure it's clean for reasembly.

Getting the shaft seals out has so far been the worst job, I've ruined a cheap set of picks I bought - lasted about 5 minutes! So, back to the drawing board - if you can't buy a decent tool, make one. So I heated, bent and filed a screwdriver into a flat ended pick - it was great, did the job in a moment. I'm well pleased - funny how silly little things make you feel achievement!

Some silicon spray helped reassembly, careful not to just push it all together as the sharp end of the armature shaft can cut the new shaft seal rendering it useless.

I spent some time polishing the armature and making sure the segments were clean, that broken pick was useful for that!

Put it all back together and it works. OK it runs, sounds OK and doesn't burst into flames or even smell like burning.

Attention turned to the pump body, it's held together by roll pins and I was a bit worried about how to get it apart. Nick Jones sugested I just hold it in a vice and tap it apart with a soft hammer, I have to admit I was dubious it would as it seemed so solidly held together but it worked without drama. In fact I was able to wiggle it apart with my hands and after a little gentle levering it was apart.

The pump is a gear displacement pump, basically two simple gears running in a 3 layer sandwich. The top layer is the critical one and really the only part you can play with. If there are any scratches or wear in the plate then pump efficiency will be lost. Polishing the plate on a sheet of glass can take out some wear and reduce the gear end float thus regaining efficiency. So I've polished a couple and we'll see if they pump better when they go in the test rig (that I haven't really built yet!)

PRVs seemt to be in short supply, well they don't come up for sale very often, the last couple I've acquired have been attached to pumps or in with other PI kit. No matter, they are simple in operation although do seem to give a little trouble every now and again. I have a few and will select the best in the test rig.

There's lots more to do but now I have dismantled 3 pumps and rebuilt 2 I will turn to the test rig and see if I can set them up to run up to pressure. The next stage is to run them for a prolonged period, say 12 hours and check results.

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