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Hi, I have a 1978 Corvette I bought a couple months ago and its slowly dripping from the grease fitting on the power steering cylinder? Its a very slow drip. Im just curious how to remedy this or if it needs to be replaced.
The zerk fitting is a perfect drip point for fluid to collect on. I'd suggest your first step is to clean the components as well as possible: hoses, control valve, and hydraulic ram. Operate the car as normal for a bit and recheck the components for fluid seepage.
I am not real sure of the timing but here is some brief history on the zerk fitting and the ball stud boot.
Through most of the C2/C3 production the control valve was manufactured at Saginaw Steering Gear Division with a zerk fitting and a special boot that had a very small slit (called the grease bleed nipple) where it met the stud. When you pumped grease into the zerk, the excess would purge through the slit. This prevented any buildup of pressure inside the control valve.
Late in C3 production (1981-82?) there was a big move toward "greased for life" components on all GM cars. So the zerk was removed and the boot was redesigned to eliminate the purge slit. Obviously, no one was considering 30 year old components requiring more, new, grease.
I believe that all service ball stud boots that are available over the counter do not have a purge slit. Many old control valve housings may still have zerk fittings. So you have a lot of potential today to mix and match housings with zerks and boots without purge slits. If you overfill the control valve with grease, the boot begins to bulge (and could easily rupture) and the pressurized grease could unseat a lip seal inside the control valve causing a power steering fluid leak.
So be very careful to not add too much grease to the ball stud on the control valve.
You have three choices to remedy this:
Purcha$e a brand-new unit.
Purchase a rebuilt unit.
Rebuild this unit on your workbench.
There is a video, step-by-step on how to accomplish this.
There are two kits that can be purchased to rebuild a C.V.
One is basic simple seals around $25. The other is more money with more labor / parts involved.
I would start with a YouTube video of how to remove the C.V. from the car.
Then find the video about rebuilding and see if that is something you are willing to do.
If its the ram cylinder leaking, save your time & money, just buy a new unit.
There is not a grease fitting on the ram.
Last edited by HeadsU.P.; May 20, 2025 at 06:45 PM.
Your simplest fix is to remove the Zerk fitting and insert a (properly sized) pipe plug with sealant on ONLY the threads (don't let any sealant get inside the control head).
That fitting is for testing during assembly operations only. IT IS NOT A FITTING TO BE GREASED. If you greased it (or some oil 'jockey' did), a seal was likely damaged internally which started the leak. After sale, that fitting serves no purpose. Delete it and hope that no functional damage was done to the control head.
Your simplest fix is to remove the Zerk fitting and insert a (properly sized) pipe plug with sealant on ONLY the threads (don't let any sealant get inside the control head).
That fitting is for testing during assembly operations only. IT IS NOT A FITTING TO BE GREASED. If you greased it (or some oil 'jockey' did), a seal was likely damaged internally which started the leak. After sale, that fitting serves no purpose. Delete it and hope that no functional damage was done to the control head.
That's Bull. All you're greasing is a pivot ball and two cups. The hydraulic portion is off to the end. Even the factory service manual shows it should be lubricated. The control valve is very simple to rebuild.
I don't know if it is bull or not. My control valve didn't leak until I greased all the fittings on the car. I did get a little over zealous when doing it and probably applied too much grease blowing the seal. The replacement Lonestar control valve I purchased does not even have the grease fitting and it doesn't leak.
The zerk fitting is a perfect drip point for fluid to collect on. I'd suggest your first step is to clean the components as well as possible: hoses, control valve, and hydraulic ram. Operate the car as normal for a bit and recheck the components for fluid seepage.
I am not real sure of the timing but here is some brief history on the zerk fitting and the ball stud boot.
Through most of the C2/C3 production the control valve was manufactured at Saginaw Steering Gear Division with a zerk fitting and a special boot that had a very small slit (called the grease bleed nipple) where it met the stud. When you pumped grease into the zerk, the excess would purge through the slit. This prevented any buildup of pressure inside the control valve.
Late in C3 production (1981-82?) there was a big move toward "greased for life" components on all GM cars. So the zerk was removed and the boot was redesigned to eliminate the purge slit. Obviously, no one was considering 30 year old components requiring more, new, grease.
I believe that all service ball stud boots that are available over the counter do not have a purge slit. Many old control valve housings may still have zerk fittings. So you have a lot of potential today to mix and match housings with zerks and boots without purge slits. If you overfill the control valve with grease, the boot begins to bulge (and could easily rupture) and the pressurized grease could unseat a lip seal inside the control valve causing a power steering fluid leak.
So be very careful to not add too much grease to the ball stud on the control valve.
Not "bull". If you are getting P/S oil from that nipple, the ball fitting is already being lubed...with P/S fluid. Grease isn't going to do anything for you. Seal it off.
Not "bull". If you are getting P/S oil from that nipple, the ball fitting is already being lubed...with P/S fluid. Grease isn't going to do anything for you. Seal it off.
I wasn't getting fluid leaking from the zerk fitting. I placed too much grease in the fitting and ruptured the boot. It then began leaking power steering fluid from around the boot area. Anyway, the rebuilt Lonestar valve has been on the car for awhile now and I haven't had any leaks yet.
I had a new control valve replaced because I was not comfortable jacking up the front end.
Next starting the engine and then Turing the steering wheel all the way in each direction. I think the shop charged me $125, and I bought the control valve. With the front end on jacks I never felt good opening the doors, my convertible didn’t like that.
Power steering fluid dripping
luckily.. as mentioned, clean everything then see reality of where leaking..
