Hydraulic piston tie rod pin stuck

I had leak in a piston for my stabilizers. I jacked the pin out of the piston end and had the leak fixed. While trying to reassemble I can’t get the pin back in. It started but now I can’t get it in or back out. Before inserting I had the pin in the freezer overnight. I need some big time help on this one.

U can buy freeze mist in a can to hit the pin. And/or heat the clevis with a torch.

Is the casting aluminum? Al has about double the CTE of steel. So, the HOLE should expand double the pin expansion.

What are the materials? Stainless steel? if so it may have galled which can tighten things right up. It looks like there is a threaded bore on the pin, you may be able to attach a slide hammer to that and tap it out. I'd but some lead or other heavy weight on the arm to help take the impact. Other than that you would need to remove the arm and take it to a press.

If you are trying for a shrink fit, heat the arm gently and evenly with a heat gun or torch, till it is a bit too hot to touch (that'll be 140 degrees or so). The pin fresh from the freezer or better still dry ice. Get everything ready because you have about 5 - 10 seconds to get it fully in place. Any delay or dawdling and you will get it half way in and find yourself in a pickle.

All good advice plus I would use Never-seize on the pin when its time to insert it.

I was installing a cleat yesterday and used brand-new hardware, got one nut about 1/4 of the way onto the 5/16 bolt and it galled. Had to cut it off with a zipdisc. Never-seize is more than your friend, its essential.

Jack it back out and see if it galled. If so, clean it up and make another go at it.

Maybe that pin has a very slight bend.
Maybe you need to heat the bore and jack the pin back out.
Check out everything, then slightly heat the bore and freeze the pin, plus use grease.

I had a hardened steel piston pin that got bent, was too tight until the piston got hot, if you heated the piston, it worked ok. But I replaced the pin and it slipped right in. These things can be a tight fit, but they are supposed to have an even tiny clearance all around, or some have an interference fit of .001 to .002 .

This kind of thing screams for a press to keep the parts parallel. But, I'd be optimistic on the thermal aided assembly with a copper hammer perhaps. For sure, this design is a 'press fit', with interference intended. I see no locking hardware (set screws, etc) in the design.
I would make every effort to support the bottom during the tapping. If the thermal difference is good, this should not take hammering, only tapping.
Be careful of the seals, when torching. Do this fairly quickly; can two folks get close, at once?

Greetings,
Mr. m. Find a socket or a piece of pipe that will fit over the pin and extend past the end of the pin. Put a bolt into that threaded hole in the top of the pin with appropriate washers/spacers and tighten the bolt. The pin should slip out. Follow the above advice to re-install. I fully agree that the pin should be put back in with the minimum of brute force. Copper, brass, lead or plastic hammer is a good suggestion.


IF you can find a gear puller with long enough arms to engage to bottom of the housing you may be able to gently press the pin back in with a minimum of heating.

diver dave said:

Is the casting aluminum? Al has about double the CTE of steel. So, the HOLE should expand double the pin expansion.

Click to expand...

This. Assuming it's aluminium, I'd hit it with an electric heat gun if possible (don't care for open flame in such an area), and jack it out using a threaded rod, nut, and length of pipe, so you're jacking against the lug. Then check the shaft for damage, and put a shine on it before trying again. The aluminium should expand at a greater rate, plus the interior of the pin won't even be warm, so it would effectively be an even greater rate than that as long as you move along. But even if you stuck it in an oven, it would still loosen.



I don't think it's an interference fit by design, or not very much if it is, as that extra hole looks like it's for a keeper.

Another possibility, the pin caught on the aluminum bore and the bore is galled.
It can be real hard to get galled pieces to seperate. Heating things really helps a lot.

++ on the heat gun. Torch in a confined area? Errrmmmm.... pretty risky!! If you must, be sure to use a fireproof shield blanket. Really helps to keep the heat focused and off the surrounding material.

If you need to use thermal help, a dry ice bath works great. Dry ice in a rubbing alcohol bath will take parts down to -110F. Lots better than the freezer. Most marine freezers won't even hit zero. Oh, and don't use bare fingers to handle those parts!

Maerin said:

++ on the heat gun. Torch in a confined area? Errrmmmm.... pretty risky!! If you must, be sure to use a fireproof shield blanket. Really helps to keep the heat focused and off the surrounding material.

If you need to use thermal help, a dry ice bath works great. Dry ice in a rubbing alcohol bath will take parts down to -110F. Lots better than the freezer. Most marine freezers won't even hit zero. Oh, and don't use bare fingers to handle those parts!

Click to expand...

Have at least one fire extinguisher close, if you are going to use a torch.

Looking at the pic. The end of the pin is threaded. So find a piece of heavy wall pipe just bigger than the pin. You will want to make it just a little longer than the pin. Then find all-thread that fits the pin. Look for grade 7 or better. You will need to get a series of heavy washers large enough to cover the top of the pipe. You will also want to stack several grade 8 washers between the jacking nut and the large washers. Coat everything with molybdenum past. Put a good load on the jack bolt. If it doesn't budge use a couple heat guns to heat it while putting more load on it. If it doesn't budge then you will have to get aggressive and cut it out.

Edit just saw t&j post saying the same basic thing.

Well, I was able to jack it out without heat. You can see the slight groove, plus one on the other side. The pin is .75 Dia x 2.40” length. (Don’t know how accurate that’s is as I’m using a Harbor Freight plastic digital caliper) How do I clean this up? The casting is steel and holds the fin on so I can’t take it off.

On the stabilzers that pin is normally push fit and held in by a keeper plate. I would get a 1/2" fine threaded set screw (screwed all the way down as opposed to a bolt), screwed into a tube nut. Place inside with tube up to the bottom of the pin, then unscrew the bolt pushing the tube and pin up and out. I would not start aggresivly hitting the machined steel casting, they can crack.

a bit of emery cloth and a fine file to start.

Take it to a machine shop and have it polished. If the bore needs to be cleaned up. You can get a wheel cylinder hone. And do it that way but it will remove some material. So you would need to be very careful not to over do it.

Greetings,
Mr. m. Yup, looks like a few burrs there. I have no idea of your mechanical skills but I would most probably try to remove the burrs with fine files both on the pin and in the hole. VERY gently and VERY slowly with a lot of fit checking, aided by a light coat of oil, along the way. I think the pins should simply push into place with little to no force. Never-seize as suggested for the final assembly.


Edit: Aw snap. Slow typing BUT great minds and all that...

HI RT
I am an engineer so no problem for me, sorry I sometimes believe all boat owners have the required skills after years of boat owning and tribulations.!!

When you say push fit do you mean by hand? The guy who installed it said I needed to use a wood block and hammer. I hope that’s not the case. Do I need to have the front end chamfered as a guide to the heim fitting?

Greetings,
Mr. m. Unlike Mr. MJ, I am NOT an engineer so I defer to his first sentence in post #15. Yes, push fit with fingers/thumbs. Regarding the "guy's" comment about the wooden block...ummm, no. Maybe that's the way HE did/does it but I'm thinkin' it ain't quite right... Push fit by hand and yes, maintain the existing chamfer on the pin.

Yes I second the smooth file and emery cloth make sure the bore is clean of any burrs as well. The chamfer well help. Keep everything clean and use a little 3 n 1 oil for install .

Thank you for all the advice. Project completed!

Greetings,
Mr. m. TA-DA !!! Congratulations. What was your final approach and solution please?

I chucked it in a spindle and cleaned it up with 320 emery cloth then some wet/dry 400 grit. I wrapped a piece of emery cloth around my little finder to clean up the bore. Tapped the pin home. One of the advantages of staying at Ladys Island Marina is the 2500 sq ft shop.