Trim Mount Shaft on Prestolite Tilt Trim

[21BaylinerCC]

Engine: 1988 Force 125hp
I decided to tackle fixing my leaking tilt/trim as a winter project. I have the pump and hydraulic lines disconnected, however the trim body and trim mount shaft seem to be corroded together. I am thinking about removing the one side of the motor mount bracket to see it it will come loose from the shaft. At this point, the trim with the tilt pistons are still stuck on my boat. Anybody else have this problem? Any solutions?

 

[Frank Acampora]

Because the shaft is stainless in aluminum and because it is almost always in the water this happens a lot. Sometimes the corrosion is not so bad and you can hammer the shaft out--but be careful not to ****-up the threads. Use a brass or aluminum drift. Many times you will need to remove the engine from the transom and heat both transom clamps to get them off. Then, press out the shaft from the trim cylinder body---careful--too much pressure will bent the body where the tilt or shock cylinder is. ALSO, the cylinders are mounted on nylon bushings. if you heat the assembly you most likely will need to replace the bushings. It is pretty much the same story to remove the upper mount bar that passes through the cylinder eyes. When you do reassembly use plenty of anti-seize or other anticorrosive compound. And unless they are perfect, replace the nylon bushings. Even slightly flawed ones tend to hang up on the mounting rod and become next to useless.

90% of the time the leak is in the valves inside the pump. Repair them first and you may not need to remove the trim and tilt cylinders.

 

[Jiggz]

As Frank mentioned, most of the time the leak is in the valve body. Did you do the leak down test posted in the FAQ section? If not, it is highly recommended before going any further.

 

[tommarvin]

There is a perfect thesis on T&T leak down here, always change the two washers first in the valve body.

They are Briggs and Stratton kit # 398188, you need two, $ 3-5 Bucks, anybody know where to get the washers only, I hate waste.

If oil is coming through the bushings, better get new bushings.

I wouldn't break anything loose,unless you have to, after replacing the two washers,

We have a 1988 Force 125, im glad your doing this before me, good luck !

 

[21BaylinerCC]

Unfortunately, I already attempted to take the tilt trim cylinders off. I sprayed A LOT of penetrate oil on it and am letting if soak for the week. I will try hammering it out again (with the brass drift). If that doesn't work, I will have to dismount the engine. Unfortunately the threads on the shaft are stripped - looks like i'll have to rethread them or buy a whole new assembly

 

[Frank Acampora]

It won't be easy but you have several options to repair the threads:

1. You can insert the mounting rod in the transom clamps and drill two 1/8 inch holes in the threaded portions. Drive in 2 stainless 1/8 roll pins.

2. You can insert the rod and drill one 1/8 hole in the bottom of the transom clamp and up through the rod. Drive in one stainless roll pin. Leave enough sticking out so you can remove it at a later date for repairs.

3. Grind the threads down and re thread the ends to a smaller size. This is stainless and really will be difficult You may need to take it to a machine shop. Use stainless fender washers and nuts

4. Drill and tap a hole in each end and use stainless fender washers and bolts. It may be more economical to buy a new piece than to have a machine shop do these last two for you

 

[21BaylinerCC]

Thanks for the advice! I will let you know what i end up doing. I am letting the shaft soak right now with penetrating oil... hopefully a week of that will help somewhat!