Gimble housing bolts/studs sealed?
 

Preparing to re-install the gimble housings.
The 2 bottom bolts had some kind of black sealant on them when they were removed..

The studs and upper bolts were a bit rusty and had no sealant.
Should they get sealant too?

Would Lifeseal be a good choice for sealant? That's what I plan to use for the foam seal.

Thx

Nope,.... No reason to seal the bolts/ studs, they're Inside the dry area, inside the transom housin' seal/ gasket,...

it was probably Aviation Gasket sealer. Merc Techs use it alot. On bolts it is sort of a sealant and anti seize and thread vibration resistor/ locker all in one.

Chris

I wouldn't use a sealant that would make it very difficult to remove in the future. You should not need any sealant.

OK on the upper bolts and studs. Only reason I ask is because the only place a see bare wood is inside the bolt holes and the old bolts/studs were rusty. Maybe water got into the bolt holes from the inside at some point before I bought the boat.

The lower bolts are going to need something. They are not in the "dry" area.
Ref item #19 here:
http://www.mercruiserparts.com/Show_...GIMBAL+HOUSING

Ah. I have never taken apart an older transom assembly with the bottom bolts. I would assume the need a sealant in that case. On the newer transom assemblies I have done, all the studs including the lower studs are inside the foam gasket. The wood does get moist if too much water sits in the bilge and the opening is not sealed or you have leaks from the outside into the transom like unsealed screws or thru-hulls.

You dont really need anything, but I would for that just in case situation. When I put mine back on, I used alittle silicone around each hole just to make sure, even tho I replaced the foam seal. It isnt going to hurt anything and you wont see it. It will be just a small piece of mind.

Thx for the replies guys. I'll plan on a small bead of RTV around the studs JIC.

As for the lower bolts, what sealant is recommended? 5200 is out. Not crazy abt 4200, but it might be OK.
I'll already have a large tube of Lifeseal opened and ready, but haven't heard of anyone using it for thru hull bolts..

Ayuh,.... Be careful usin' sealant on those aluminum bolts/ studs, they're a part of the anode system,...

This may sound like a dumb question, but if I have a Mercathode sys, are the lower alum bolts still considered part of the anti-corrosion sys?
My old boat had alum lower bolts and the bolt head had a stud on it for a "zinc sacrificial element" (I think that's what it was called) could be screwed on.. The lower bolts on my Bravo don't have a place to screw a zinc element on.

is this a small or big block boat? more important-alpha or bravo drives. if alpha the bottom bolta are aluminum and go thru housing inside the foam seal and should be sealed. they come with a rubber gasket thingy, but i would add sealer. for zz28, the bravo lower bolts are threaded into the housing and don't go thru.

These are 454's/bravos from 1990. The bottom alum bolts have nuts (also alum) on the inside after they go thru the inner transom plate. The bolt heads have a square shape under their round head that engages the square hole in the gimble housing.

Another member mentioned the new bolts come with a rubber washer/gasket and that a SMALL amount of sealant should be applied to the rubber gasket.

When the drives were removed, I had to dig a little black rubber (or maybe sealant) from the bottom holes in the transom.

These bolts appear to be exclusive to the early drives (ser# 0B664190 THRU 0F729999 )

I have the same year setup. I replaced all those bolts last year when I had mine off. I'm almost sure you are right that there is a rubber washer/o ring that goes on that bolt. I remember thinking the same thing that they are not inside the sealing area so they have to have something.

I can't remember if they came in the bolt kit ($20 / bolt w/ anode cap) or I had to buy separate. I think it was separate because I had to go back to the shop to find it. I'll look on my boat /pictures today and see if it jogs my memory. I know I did add sealant on that bolt too....I think 4000 or 4200.

Dean

The lower bolt that has a small stud on the head for the anode to screw on is yet another version during that time period. Mine has no provision for an anode.

I just got off the phone and the rep said the rubber washer does not come with the bolt, so I had to order it separately.

the answer to your ? yes you put 4200 on then but only on the inside so then or fi you get allot of water up to the bolts the water dont seep past the bolts and sep into the wood..ever see how allot of guys on here ask if they ever seen the bottom bolts or studs rot off,,this is why you seal them.a circle on the outside and a circle on the inside and then the threads ..

Sounds like a good plan FIXX. Hoping I never get enough water in the bilge to reach the lower bolts but sh!t does happen!

Correction: Installed the gimble housings last weekend. The 2 lower (alum) bolts are within the perimeter of the foam seal. They use rubber washers to seal the bolt heads. If the rubber washers leak, water enters the "dry" area.

I used the correct rubber washers and a bead of 4200 to make sure they seal.

Before installing the inner transom plate, I used 4200 around the lower bolts in case the bilge takes on a significant amount of water like FIXX suggested.