Leaking clutch master cylinder

[Toysx2]

The clutch master cylinder on my 68 FJ40 is leaking between the plastic reservoir bowl and the cast iron body of the cylinder. I have tightened the internal nut, but that does not seem to have helped. The cylinder is new--I replaced it because the other one was doing the same thing. Can I put silicone or something similar in the joint as a sealant? The cylinders are from BAP. Could that leak be the source of air getting into the system making it necessary to pump the pedal to work the clutch?

Thanks,

Ernie

 

[splitshot]

Is it the original reservoir and seal that was taken off the old master? The seal could be dried out or the res. could have a hairline crack in it.

 

[Toysx2]

Is it the original reservoir and seal that was taken off the old master? The seal could be dried out or the res. could have a hairline crack in it.

It is a new reservoir with the new cylinder. I'll take it apart to see if I can spot a crack. Was wondering if I could use some kind of sealant that would not be affected by the brake fluid when I put it back together.

 

[splitshot]

Maybe someone else can pipe in on the sealant, all I know is brake fluid will even blister paint if left on too long.

Check out #42 gasket also.

 

[Tools R Us]

Define "leaking" some seepage is common on the early type cylinders, if it's enough to form a drip it's excessive. It was an assembly from BAP, I would return/exchange it and see if the new one is better? Sealants can cause more problems than they solve on brake systems, brake fluid breaks down some of them and can contaminate the fluid, plug up small ports. In my experience seepage at that point has no effect on performance.

 

[Toysx2]

Define "leaking" some seepage is common on the early type cylinders, if it's enough to form a drip it's excessive. It was an assembly from BAP, I would return/exchange it and see if the new one is better? Sealants can cause more problems than they solve on brake systems, brake fluid breaks down some of them and can contaminate the fluid, plug up small ports. In my experience seepage at that point has no effect on performance.

I stopped by Nippon Motor Service here in Tucson a while ago and spoke with the shop foreman. He said that any seepage at all is not acceptable. He said that he would replace the master cylinder(don't try to seal it). He also said that he had used BAP parts without any problems but suggested maybe trying some other source. After changing the master cylinder, his suggestion was to thoroughly clean all of the fittings, then lock the clutch pedal in the depressed condition over night and then re-check for any wetness. His bet was on a loose fitting. I guess I'll give that a try.

Ernie

 

[Tools R Us]

In a perfect world, perfect seals on everything would be great! In this case the connection we are talking about is a reservoir, so if anything has slight pressure from the fluid sitting in it, the connection is above the intake port, if any air were somehow sucked in it would harmlessly raise in the fluid, wouldn't cause a loss of performance. I have seen them work fine for years with a slight seep at that connection.

I have had great luck with BAP cylinders, some are Aisin with the name machined off.

 

[Toysx2]

In a perfect world, perfect seals on everything would be great! In this case the connection we are talking about is a reservoir, so if anything has slight pressure from the fluid sitting in it, the connection is above the intake port, if any air were somehow sucked in it would harmlessly raise in the fluid, wouldn't cause a loss of performance. I have seen them work fine for years with a slight seep at that connection.

I have had great luck with BAP cylinders, some are Aisin with the name machined off.

Certainly sounds reasonable to me!! I think that I will pursue the possibility of leaky line connections first. I just spoke to the folks at BAP, I guess the length of the original warranty is not extended when you replace the original part. So I really don't want to end up with a pile what may be good master cylinders when the culprit may be somewhere else! The counter guy at BAP seems very experienced. He said that he has seen many defective slave cylinders that do not leak. His suggestion was to replace that part of the system.

Thanks,

Ernie