['87 Porsche 944]
I think this is a general question: is grease on the brake pushrod a bad idea? I figure moly grease would be best, maybe white lithium.
I noticed some rust on the brake pushrod - the one that goes into the master cylinder. It occurred to me that a light coat of grease - down at the tip - would ameliorate the rusting, but being in such close proximity to the hydraulics, might be a bad idea.
I would not do anything that might contaminate the push rod. See if instead, you can replace it with a stainless steel one.
The pushrod is outside of the hydraulics so a little grease won’t hurt. Since it is INside the car, don’t use moly, it may drip off and stain your pants leg. White lithium would be better. It really isn’t necessary. Painting the pushrod (except the tip) may be better.
I guess it probably wouldn’t hurt, but I wouldn’t. It’s what, 27 years old? How much rust? I’d just sand it clean and let it slowly rust again for 27 years. Maybe paint it with something rust-resistant (POR-whatever).
I agree with Texases. There is a reason why boots are usually at the end of the rod where it enters the cylinder. It’s to keep dirt out. Grease attracts dirt and can liquefy over time. Now you have more abrasive dirt inside the boot. While the rod is out side cylinder, sand off the rust, wipe it down and wait 27 more years, we never apply grease on the rods entering the cylinders of hydraulics on our tractors. Just keep them clean. I use grease for rust proofing surfaces and lubrication but never areas like this. Maybe a little too extreme on my part…but better safe IMHO.
This is a case where if it isn’t broke, don’t fix it. Do nothing. If the push rod is so rusted as to be unusable, replace it. If it is the pushrod I’m thinking of – i.e. your car’s set up is similar to both by Ford truck and my Corolla – that pushrod comes with the master cylinder, so you’ll get a new one next time the master cylinder is replaced anyway.
thanks - especially about the reminder that grease retains dirt @dagosa . Will probably let this go. I like the SS rod idea… yes @texases it’s an '87.
@GeorgeSanJose this rod inserts into a sleeve in the cylinder… i.e. it doesn’t come with the new cylinder.
Thought I’d add : recently discovered my clutch slave pushrod was rusted solid to the (I think) clutch fork. There could be reasons for that, but I’ll be putting some moly - or lithium - grease there… and seeing how it does.
I’m guessing that the portion that is rusting does not contact any other moving parts…there’s a “shiny” part of the rod that slides in and out of the MC, and the “rusty” part is beyond that.
If so, it really doesn’t matter if it gets rusty, so long as it doesn’t rust through, which I do not see happening.