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What do you use on hardware threads and orings?

B

bicounty

Member
I am ready to put my drive back together. I was wondering what I should use on the threads for all the bolts. I have Loctite and I have a can of Mercruser perfect seal. I was thinking a lite coat of the perfect seal on the orings and seals. Should I use Loctite or perfect seal on the hardware threads? Should I put anything on the big oring that goes between the bottom of the steering/water tube and the lower unit? The oil that came out when I took it apart looked brand new. I just took it apart to replace the steering tube and roller bearing in the intermediate housing and to clean it up and paint it. I figure I will put it together and the preasure and vacume test it. Any tips on pressure and vacuum testing? It's a dp290 drive.
 
Need a bit more information...., such as how far down has the drive been taken apart?
Is this a 290 or 290A transmission?

The threads to be mainly concerned with will be:
  • the three 5/16" aft-most lower unit fasteners. Two will be just inside of the shift cover, the short one will be exposed.
  • bearing box clamping collar bolts if pre- A transmission.
  • the two small screws that hold the water neck fitting to the suspension fork.


If in salt water, Perfect Seal should work well on these threads, O-rings (although O-rings require zero sealant), and mating surfaces..... in fact, you can use it on all threads if you want to. Over-Kill, but won't hurt other than slowing down removal next time.

The lower pivot tube fat Oring remains stationary against the pivot tube. Glue this to the lower unit bore so it cannot slip out of place.

The water neck fitting special beaded gasket does not remain stationary, so this needs to be greased at the underside where the bead contacts the pivot tube.

Pressure/Vacuum test is a "Leak-Down" test so be sure to include a time frame with the gauge installed, and for both press/vac.
Rotate main drive gear, eccentric piston and prop shafts during the test.

The only area where I use Loc-tite would be for the main drive gear/male yoke fastener (special cap screw), and this would be during your final rolling torque procedure.



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Thanks Ricardo: I always seem to be confused about the exact drive I have. The trans. tag says DP-A 195. I have the square end caps on my trim cylinders and I was told it was a 290 drive. I just separated the 3 sections. I didn't take the upper or lower apart.
outdriveupperunit.jpg
 
If in salt water, Perfect Seal should work well on these threads, O-rings (although O-rings require zero sealant), and mating surfaces..... in fact, you can use it on all threads if you want to. Over-Kill, but won't hurt other than slowing down removal next time.
Click to expand...

Ayuh,.... Great stuff, that seals, as well as protects....
 
Yes, that is a 290A transmission. I can tell by the 1 pc bearing box/clamping collar.
You are probably due for a re-seal, main drive gear bearing inspection, eccentric piston seal replacement, and a good look at the brass split ring keeper.
Your universal drive shaft is also likely ready for bearing cross replacement.
People ship these to me for this work, if interested.
Due to your area and the limited number of shops who want the AQ series work...., it's usually very cost effective.


Bill, I too prefer the Perfect Seal.


NOTE:
While tempting, DO NOT use the automotive versions of Anti-Sieze or Never-Seez products.
I love these, and I use these.
However, the good ones contain conductive materials, and when used below the water line, the name changes to Always-Seez!
Use the Marine Version if you must.



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