Trim Cylinder Fitting Problem

[75TowerOfPower]

I have an old '74 Mark Twain boat with a '75 115 HP Merc motor on the back and the trim and tilt cylinder has a stripped out connection.

I know the threads on the female end are 1/2-13 straight threads and the hose just has a flare on the end. So basically the clinder housing is aluminium and the steel nut stripped the threads.

Do you guys thinks its possible to tap it out to M14 maybe and use a metric nut to hold the flared end on to the clinders end?

I was hoping to be able to do this on my own and not have to pony up too much money. Hopefully I can solve this other wise I need to go to a hydraulics shop to have them fix it.

I was thinking of popping my head in to Aeroquip thats close to me and seeing what they say.

 

[Chris1956]

Re: Trim Cylinder Fitting Problem

They were prone to strip out, as you have found. I would think a brass flush bushing would be the way to go. The ID of the bushing should fit the hose fitting, and you can tap the cylinder (hopefully) to receive the flush bushing. If you can get this to work, epoxy the bushing into the cylinder body.

Alternatively, used trim cylinder are available, and there are rebuild kits. You need a special tool to install the teflon piston seals, however.

 

[75TowerOfPower]

Re: Trim Cylinder Fitting Problem

I am thinking maybe a helicoil? Well what if I just did a JB weld job until I find a possible for sure solution.

 

[Chris1956]

Re: Trim Cylinder Fitting Problem

The high pressure hoses have a fair bit of pressure. The JB Weld might hold, if the threads are not completely gone.

 

[75TowerOfPower]

Re: Trim Cylinder Fitting Problem

Well I found a solution, I found a fitting that goes from 1/2" thread inverted flare to 1/4NPT. The 1/4NPT will just bare fit in since the old threads are stripped out. So since NPT is on a taper I can get good contact by tapping it and using some pipe dope to install the fitting.