BW35 new sump gasket leak challenge

As described in another thread I also had a BW35 mysterious leak problem. After fixing it, I closed the box with a new sump gasket as to workshop manual instructions (vaseline and torque): It was leaking - really pouring leaking. Tried some more torque, but no change. After draining and taking things apart I realised that the new gasket is so hard and stiff that I am sure it will never seal anything against a pressed steel part. However it is brand new, purchased from MGBD - Mark Gray, so I am also sure it is exactly as expected.

I failed to notice that they stock both cork and composite. Old one was cork, new is composite. I am sure cork would be more/adequately flexible...

Still I must be doing something completely wrong. What might it be?

It has a green and a black side. Is one up and the other down, or is that just a matter of taste?

Any lead, thank you...
 
Unbelievable: Are there really no experiences, opinios, or recommendations about composite gaskets?
Not used the composite gasket, always stuck with the cork which work well when fitted correctly.

Make sure the sump pan is flat along the mating surface, if it is not then make it so.
Use hylomar ( universal blue ) on the pan face only then refit and tighten the bolts until just over hand tight then another 1/4 turn.
Don't torque them as this tends to bend the pan upwards.
 
Ordered two new cork ones simply because even if I try to flatten the pan (slightly deformed/uneven by all bolts - previously torqued?) I never think I can make it good enough. And hylomar or something similar of course. Only still I wonder who would ever use a composite gasket, unless with a pan in cast aluminium.

Lastly: Thank you :)
 
Hello Anders, A couple of years ago or I had the dreaded leak on the 35 auto box (I reckon there is no absolute cure for this) I tried using a "neoprene" rubber gasket (twice) and both times they failed within 2 weeks!! so, back to the cork gasket however, it is imperative that the flange is absolutely flat, what I did to get the "doming" area around the holes flat was to use a 10mm bolt and nut, place a suitable socket underneath the flange, place some washers on top and then tighten the bolt until the domed area becomes flat, it takes quite some time to achieve but I got mine to within less than a thou gap, I didn't use any hylomar or anything like that but, as I said, I don't think they can be cured completely, they don't call them the "wet box" for nothing.
Regards DAV8 Dave
 
Have just refitted my sump with a new gasket after doing this about a year ago and forgetting to prepare the pan first.
What I do, have done this on the engine sump as well with no leaks, is to fix the overtightened bolt holes as DAV8 mentioned above. I place a socket which is just narrow enough to fit in the gap between the pan side and the flange return. This socket sits on a a heavy piece of steel, an anvil vice would do, on top of this I place the pan so the hole lines up and I have have an 8mm multi-spline bit which has a sharpish radius from 8mm to about 13mm (the size of the bit shaft) which I insert into the hole and give a couple of good hits with a hammer until the hole reverses and it’s “doming” is about 1/4mm on the side opposite the gasket face. This seems to straighten the pan edges but I always check with a straitedge. For the cork gasket I fix this to the pan the day before with a smear of Permatex aviation adhesive, and then prior to fitting the pan I smear the face of the gasket with Hylomar blue. I tighten the bolts up until the spring washers are just flattened which seams to be just nipped up but not too tight.
 
Back
Top