Separating Volvo upper and lower drive sections, DPS-A

[BRICH1260]

Need some advise. I'm trying to separate my DPS-A drive, upper and lower halves. I have removed the two bolts and four nuts as the manual instructs. I cannot get the two pieces apart. I have tried tapping with a rubber mallet and gingerly tried prying apart with a stiff putty knife to no avail. I have been going slow and easy trying not to mar, gouge or break the aluminum castings. Anybody had a similar situation that found a working solution. I am wanting to replace the inner seals as I am chasing a water intrusion problem.

 

[Lou C]

I have had to do this on an OMC Cobra drive. The way I did it without breaking anything:

Have the drive mounted in a drive stand, home made is fine.

Get 2 bolts that fit in the front mounting holes on the upper gear housing. Secure them with nuts so the bolts stick out. Then put a long piece of all thread in the hole for the trim ram rod in the rear of the upper gear housing. Now get 3 scissor jacks and put one under the 2 front bolts and one each under the all thread rod on each side of the rear of the upper gear housing.
Jack each one a little at a time till the upper pops free. It may be stuck on a dried up o-ring. Just make sure you removed ALL the bolts first!

 

[Scott Danforth]

I pull my drive apart often to keep any corrosion at bay.

plastic wedges help (plastic or wood door shims) for housings with corrosion on the pins.

I use permatex #3 (aviation sealer) on all the joints. its what Volvo uses between all the cases (or at least what they used to use)

 

[BRICH1260]

Scott, I just tried the wedge suggestion, tried to drive a plastic logging wedge between, it just bent my wedge. Lou, I'm gonna have to get the sissior jacks rounded up before I can try your method. I'm thinking that corrosion is what is holding it together. I'm gonna try to spray some pub blaster to maybe CLR in the seam to weaken the possible corrosion and try it again tomorrow. While I use it in fresh water now, it's first couple of years it lived in a salt environment. I'm thinking the salt is what is causing the binding condition.

 

[Lou C]

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Here's a pic so you can see how I did it. This way you're using the strongest parts of the drive housing to apply force

 

[BRICH1260]

Lou, thanks for posting the pics, it really helps me visualize what you were describing earlier. A couple things I see, while similar, my DPS-A does not have the long bar ram attachment hole passing from side to side through the rear of the drive. It is only a 2-3" deep hole in each side. I think the principle that you are describing is what I need to take away; find a way to slowly force the two pieces apart using the thicker more robust areas of the casing as not to break it. Right now I am soaking the joint with pb blaster and may try CLR to break up the suspected corrosion. What do you think about applying a little bit of torch heat to the seam to help break it?

 

[Lou C]

I would just be careful, give the penetrating oil a chance to work, I am not familiar with these drives so it is hard to determine what is causing it to hang up. On the Cobra and also on the Volvo SX which is similar in some respects, if you look at the second pic with the upper gear housing removed, you will see a bearing carrier that has slots for 3 orings. On mine I think that exhaust water would go past the lowest one and there would be salt deposits there that would cause it to be difficult to remove. I tried all kinds of wedges, prybars, etc and nothing was getting it to budge. I realized the only way to safely do this was to put pressure on the strongest parts of the upper gear housing. Given that these new drives do not have a bar going through the upper gear housing, then I'd get 2 pieces of all thread the right diameter to slide into the holes on each side. I looked at the parts diagrams for this drive and the places I could imagine that it might get stuck were the mating faces of the upper and lower, (why a good penetrant may help try Kano Kroil, or Freeze Off) and perhaps some of the gaskets for the water passages as well. There seems to be an o-ring on a bearing housing that it could be stuck on if water can get around this area, the upper and lower may only be sealed with the 2 oring gaskets for water passages. Just make sure every last bolt was removed and if you do use jacks, apply pressure very gradually and evenly. Make sure they do not press on the cav plate for the lower gear housing, that could snap easily.

​Heat may work but again be careful, you don't want any area that has bearing seals to get heated up excessively. Is there any movement or flexing at all?

 

[BRICH1260]

I was able to get about 1/8 gap between the two halves. Still to small for my chainsaw wedge, so going to try some wood door/window shims tomorrow. Then move up to the thicker wedge. If I ever get apart, you bet I will add a good coat of permeatex between the two halves for ease next time.

 

[Lou C]

Permatex aviation on the bolts. OMC triple guard grease on metal mating surfaces

 

[BRICH1260]

I got the halves separated finally. I had corrosion in the four bolt holes of the lower half, dried crusty white calcium looking stuff. So tight against the stainless upper unit bolts that it "welded" the halves together. After days of wedges and pounding, I realized where it was sticking. Here is how I resolved the problem.

I inverted the drive, skeg up by a pulley system. With a syringe full of CLR, I injected the CLR solution onto the bolts and allowed it to flow downwards into the holes. After a bit of soaking, the CLR broke up the corrosion which allowed me to drive two wedges between two units and separate them. All parts will get a good coating of grease next time. Should make it easier next time.

 

[Lou C]

No Title

Good work! Pick up a tube of OMC/Bombardier/Evinrude Triple guard grease and coat those bolts with it and it will come apart easy the next time. I used this on the prop shaft (boat is moored in salt water all season) and its still there, even after a season in the salt. The best waterproof grease I have ever used.