Fordson SM Clutch Play

[smchris]

Hi John

After I reassembled everything yesterday I gave it a reasonable run around the fields to warm it up - it only leaks when it's actively running - and parked it over the concrete apron to see if it was leaking while warm. It was; the oil is dribbling out between the back of the front plate and the front of the sump, right in the centre. But which is the primary source, I cannot say.

It began to leak like this after we removed the sump in 2021 to replace the liners, pistons and rings (it was burning oil terribly and the bores were really worn, probably because the bleed-off pipe was cracked and leaking diesel into the crankcase, thinning the oil...).

So we may have disturbed the gasket on the front plate when replacing the sump (which had new gasket all round); or the sump gasket itself was not fitted correctly /moved during reassembly (though I checked as we went and did not see any evidence of this). Or both.

Thoughts?

[shepp]

The front plate gasket should not have been affected unless you slackened off any of the front plate securing bolts to assist removal of the sump. If it did not leak from the front plate before you removed the sump to fit new pistons and liners then it is very unlikely that a leak has sprung up now from that gasket.
I would say that you are looking at the half moon cork gasket at the front of the sump not sealing correctly, which is something I suggested some time ago that you should check before assuming that it must be the crankshaft front seal. If you remove the sump to fit new gaskets use Blue Hylomar on reassembly to provide some degree of insurance against a leak.

[smchris]

Thanks.

I did find one missing bolt on the front side LHS of the front plate as you look at it, so there is a reasonable chance that the gasket has gone through somewhere, if that missing mounting has allowed it to move.

Your point is a good one though, and it seems reasonable to condemn the sump since that is the one thing that has changed. Pain to remove though, isn't it. I shall be glad when this job is over!

[Billy26F5]

I would say that you are looking at the half moon cork gasket at the front of the sump not sealing correctly, which is something I suggested some time ago that you should check before assuming that it must be the crankshaft front seal. If you remove the sump to fit new gaskets use Blue Hylomar on reassembly to provide some degree of insurance against a leak.

I would do this too, if you get it from Agriline (as we did for Super Billy) you'll need to cut it to length, others are probably similar but I don't know that. I recommend you remove the tie rod and radius rod first and then lower the sump. We did this with Super Billy and although we had a struggle with the radius rod (one of the nuts was rusted on and it ended up splitting) I don't remember any particular problem with lowering the sump. Hopefully it'll be easier for you since you already had it off recently.
Sandy

[John b]

Hi Chris, if you do find the gasket needs replacing on the front plate, this is the one I have

[Billy26F5]

I think that's the right one, but I hope it's just the cork, as taking the plate off just for a leak isn't fun!
Good luck Chris.
Sandy

[smchris]

Taking the sump off for a leak isn't fun either! I think it was also leaking down the back of the timing cover, so dealing with that was helpful too, but I wish it had been exclusively that. Let's hope that the cork is malplaced and a new gasket and core with some jointing compound cures it...

I'm waiting for the bits to arrive. Hopefully before Saturday and we can nail it then.

I just want this machine back in service before the season kicks in. The hedges and grass are going to explode with all this rain...

Meanwhile, thanks John for digging out that gasket. Let's see what doing the sump achieves. If you hear a howl from Essex at the weekend, you'll know the diagnosis...

[Billy26F5]

Taking the sump off for a leak isn't fun either!

I totally agree but the sump is easier than the plate.
Hope the leak is fixed soon.
Sandy

[smchris]

Bit of an update; sorry for the prolonged silence.

I did the sump gasket and put in new lower cork and rope sealson the crank front and rear... and the leak is worse!!

I must have buggered up installing the crank seals because it's literally dripping out when running from the drain hole in the clutch housing. A reasonable puddle forms beneath quite rapidly. A slower drip comes from the front end.

Back to square one; looks like I'll be dropping the sump again. I can only think that I did not install the rope or the cork accurately.

Am I right in thinking that the gasket goes on first (on the engine underside), then the cork at the front, then the sump goes on, with the rear rope seal already in place in the sump body?

[Billy26F5]

Yes, but you need to leave a bit of extra for both (1/32" at each end of the rope seal). I would like to think the clutch linings will be ok but I wouldn't be too sure with that sort of a leak.
Hopefully it's only a minor problem, as it's never fun to have to take everything apart again.
Sandy