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Grease zerks for trailing arm monoball bushings
I have monoball bushing in my trailing arms that get noisy at times.
Has anyone put grease zerks in them? Would this weaken the arms? They are suppose to be dry, but I 've been spraying some lube in there to quiet them so I figured why not just put zerks in there. Car was track/street, but is now just street.
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Rod 1986 Carrera 2001 996TT A bunch of stuff with spark plugs |
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It's a 914 ...
Join Date: Jan 2008
Location: Ossining, NY
Posts: 4,728
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What are you spraying into them? And where would you put grease? Thinking of the spherical bearings I put in some 930 trailing arms recently, it might be challenging to direct grease from a zerk to make sure it actually gets to the bearing. Just dumping grease into the “cartridge” that holds the bearing may not direct it into the bearings.
As you state, spherical bearings are intended to run dry. They indeed can be noisier than stock bushings. |
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Join Date: Feb 2025
Location: Slickville,Pennsylvania
Posts: 103
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Installing grease zerks in monoball bushings can compromise their integrity and potentially weaken the arms. Monoball bushings are designed to be dry, and introducing grease can attract dirt and debris, leading to premature wear. Instead, consider replacing the bushings with new ones or exploring alternative solutions, like using a different type of bushing or arm design.
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Good points guys.
Even though I have the engine/gearbox out and brakes off, I really don't want taking the trailing arms out to be on my to-do list. I would have to drill through the arm and outside of the bearing so the grease could get to the inside which is the moving part. Then I should probably pin the outside of the bearing so it didn't move and misalign the grease hole. Really should take the arms off for this and have my machine shop do it properly. At that point I could replace them, but the monoballs would get destroyed during removal and they were expensive. More so than the expensive replacements. I guess I'll pull the bolts and give them the brake clean / compressed air treatment. Then spray some lube at them again. What would you use for lube? Thanks for listening guys.
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Rod 1986 Carrera 2001 996TT A bunch of stuff with spark plugs |
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I wouldn't but TriFlow if you do. Teflon based and doesn't attract grit.
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Join Date: Mar 2016
Posts: 918
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If this joint is a spherical bearing or heim joint, I've seen them on other race car applications with a zerk drilled into the housing. The "ball" had a "line" scored around its circumference that allowed the grease to travel around the ball to lubricate the whole thing better.
I was told that grease and dirt make a wonderful grinding compound, and I would be better served using a standard heim joint with a teflon liner. Otherwise adding grease after every race would be the only way to keep it clean. |
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Join Date: Feb 2025
Location: Denver, Colorado
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Thanks for this info.
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Counterclockwise?
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Quote:
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Rod 1986 Carrera 2001 996TT A bunch of stuff with spark plugs |
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Adding grease zerks to trailing arm monoball bushings can quiet them down, but it’s a mixed bag—drilling for zerks will remove a small amount of material, which can slightly weaken the arm if not done in a low-stress area, and monoballs are generally designed to run dry with PTFE liners rather than grease like traditional roller bearings. If you really want to add them for street use, position the zerk away from the highest load path, use minimal drilling, and keep in mind that once you introduce grease, you’ll need to maintain it regularly to prevent grit contamination that can wear the 7252 BM bearings or liners faster than running them dry.
Last edited by maoliz; 08-15-2025 at 01:02 AM.. |
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Join Date: Oct 2016
Location: WA
Posts: 369
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I have Rebel monoballs and rear bushings in my '87. I have a quiet clunk or thud when taking off from a start. Is this the noise people experience with trailing arm monoballs? Everything is tight...
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