Crankcase pressure and main seals

[fatso]

I posted this on itocuk as well, but I think I need as much help as I can get

This weekend both main seals on my 2.8 started leaking at the same time. Since they were both at the same time it seems reasonable that it was caused by excessive crankcase pressure. I checked the breather at everything looks fine.

There's only one breather on the engine from the rocker cover right?

I had a wet air filter though, so my guess is that the negative intake pressure sucked the rubber diaphram valve shut that's at the back of the rocker cover.

I haven't done a compression test yet, but the engine runs fine. If you hold your hand over the dipstick tube you can feel pressure pulses and get a mist of oil on your hand. Can someone check their engine and see if it does this also? If you plug the tube it doesn't build up pressure, but if you hold your hand infront of it you can feel some pressure pulses.

Anyone have any experience with plugged breathers? If the breather was plugged and oil was forced past the seals will they seal again now that the breather is free?

I'm not sure if it's too late to save the clutch even if the leak stops, but I want to find the root of the problem before I replace any parts.

Thanks a lot for any help.
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1991 Bighorn LWB 2.8 TD 4JB1-T

[geeves]

Its rare for a leaking rear seal to contaminate the clutch but it does make a huge mess. Drilling a small drain hole (2mm) in the bell housing below the clutch fork will let the oil drain but you should seal this for water crossings. Ignore the clutch unless slipping.
front seal is more of a worry if you have a belt driven cam instead of chain as the oil can kill the belt.
Isuzus are known for exessive cranck case pressure but yours sounds ok If its bad there would be vissable smoke when you take the oil cap off. The wet air filter could of contributed How wet did it get and did water get into the cylinders. 1 tablespoon in one cylinder will kill the engine less can do damage.
Try a good quality stop leak formular first as its easier than dropping the gearbox to do the rear seal. If it works still check the cam belt for oil and replace if any evidence of oil.
good luck

[fatso]

Thanks for the info. The air filter got quite wet, but no water got into the engine.

I had a problem with the clutch slipping at one point, but not anymore. I drilled a hole in the bell housing as you suggested and tapped it for a 1/16" NPT plug. A few tablespoons of oil came out at first, but it has all but stopped. I'm hoping what's coming out now is just what is left in there, running down the bellhousing. The front seems to have stopped leaking for now. I just replaced the timing belt, but I guess I might have to do it again if it's contaminated.