'76 280SE

[chrismsullivan]

Awesome, thanks again Oscar. I'll endeavour to piece it all back together this afternoon and let you know of the outcome.

I've decided that the two larger o-rings that we were discussing can be used - Once for the rear seal on the back of the pump as you highlighted and the other can be used to replace the cracked plastic band.
It's not a tight fit, but sits in the space nicely and should be able to move once the piston is re-inserted into the housing.

Thoughts?

[oscar]

I'm not real sure what to do about that plastic band.  Although I'm one for shortcuts, make do etc, I'd rather see what some others recommend coz I don't know what that band does.

One more thing, part number to that gasket for the rear of the pump is 1100160780.  Link

[koan]

The plastic band that sits around the main piston has cracked and can come off.

That started life as an o-ring. It ends up flat (and brittle) as does the one in the base of the pump. The two o-rings in the kit are the replacements.

No idea what the remaining thick ring is for.

koan

[chrismsullivan]

Help!

the pump is all back together with no problems. It seals nicely and ther eare no blockages.

Upon mounting to the engine and fastening the hoses, it does nothing... It doesn't seem to be sucking.

[TJ 450]

I'm not sure, but it may be worthwhile opening the bleed valve on the level control valve up the back of the car, attaching a piece of clear tubing and directing it into a container. See what happens if you run the engine then.

Caution: If your SLS springs are weak, the car could sink down abruptly.

Tim

[oscar]

Not disagreeing with TJ at all but I reckon the pump just needs priming.  Plus I'll state the obvious, you did put the coupling in too didn't you?

To prime the pump I'd take off the supply pipe from the pump and drizzle oil into the top, crank the engine over but don't start it, (remove coil lead to make sure it doesn't start).  It wont need much oil.  Do that a few times and reconnect the supply line.  It should start sucking through not long after the engine starts.  

How did you go with the seals?

[chrismsullivan]

Thanks guys.

I thought about the valve at the back but thought that it was something else as while the car was running with the supply line to the rear disconnected there was still no fluid flowing through.

I'll try priming it and let you know.

No probs with the seal, although the new o-ring on the main piston got caught on the lip of the pump rear when I re-inserted it and a little bit sheared off the edge of the ring. Oops!

If priming fails, I'll try the valve at the rear.

[chrismsullivan]

I connected the supply line to the pump and drizzled fluid into the top hole that feeds the lines to the rear. Disconnected the lead on the dizzy, cranked it, topped it up, cranked it again and repeated a further two times.

From there I reconnected the dizzy and wrapped some rags underneath the pump in preparation for collecting fluid pumping through.

Fired her up and success! the pump is flowing! Reconnected the rear supply line, fired it up, checked that it's flowing back into the reservoir andit was all good.

I then did the obligitory bouncing on the towbar check and the rear end is considerably firmer. Moreso than it was before. So, I guess it's all working. Best of all, no leaks tha tI could spot. I'll have to have a closer look during daylight.

Guys, thanks so much for your assistance. I'd be toiling away for months if it wasn't for your helpful hints.

Next on the list is to replace the front belts, check the disks for thickness and the pads and try to patch up a rust hole that's starting to form on the front drivers jack point and in the wheel well in the boot.
From there, she should be ready for a RWC check.

Once she's road legal again I'll be doing some serious cosmetic work, with a respray and further interior trim detailing.

Thanks again.

Chris.

[oscar]

Great news Chris.

[chrismsullivan]

OK... We've takena  backwards step here. I went out this morning to check for leaks during the daylight. There is still a leak coming from the front cover of the pump. It's just dripping out from the bottom of the pump.

It has the new o-ring in there, so I'm a little stumped as to what to try next to seal this bloody pump up.

[koan]

OK... We've takena  backwards step here. I went out this morning to check for leaks during the daylight. There is still a leak coming from the front cover of the pump. It's just dripping out from the bottom of the pump.

Could be the shaved o-ring. I would have been surprised if it didn't leak, those two o-rings are at the delivery pressure of the pump, unlike the cover o-ring and rear seal which aren't under pressure.

koan

[chrismsullivan]

Thanks Koan..

Righto, I'll rip it apart, again, and try to find a replacement o-ring for the one that was damaged. Hopefully that will remedy the issue.

[chrismsullivan]

OK, it looks as though I've fixed the leak.

I found a replacement O-Ring, but the bloody thing snapped on me!

So, I went for a backyard fix approach. I removed the good o-ring from the bottom of the pump housing and replaced it with the one that had been damaged when reinstalling the pistion into the housing previous and then placed the good one on the piston.

It all went back together well and there are no apparent leaks.

My question is this... I thought that there was no real reason why the bottom oring should allow fluid to escape back into the engine as there is that new double tipped seal in there to preven such a thing happening.
What are your thoughts??

[koan]

My question is this... I thought that there was no real reason why the bottom oring should allow fluid to escape back into the engine as there is that new double tipped seal in there to preven such a thing happening.

The shaft seal is not under pressure, its on the suction side of the pump. When the o-ring at the back fails the seal gets output pressure and can't hold it back.

koan

[chrismsullivan]

Thanks Koan. So you're telling me that it's likely to be leaking back into the engine?