V-drive reassembly
- Parts List
- Part I: removing the unit
- Part II: preventative maintenance, protecting the cooling jacket, reinstallation, and aligning the unit
- Part III: After Launch
I've finished rebuilding my V-drive, and thought it might be worth writing up my notes while the memory is still fresh. I found a bad seal at the input shaft. One of the CV joints inside the case was bad too. I don't think the CV joints get well lubricated the way they are mounted. There is no way to replace the CV joint unless you completely disassemble the V-drive, but the seal can be replaced easily.
This project turned out to be a much more difficult task than I had originally expected. I had to custom fabricate tools to V-drive reassembly remove the shaft sprocket nuts. I also had to buy a torque wrench capable of measuring 200 lb-ft (JC Whitney $12). I should have bought a press (approx $75), and perhaps a gear puller ($30). Walter quoted me approx $650 for the labor to rebuild the unit, more or less. I figure more; the bill would probably be closer to $1000, plus $400 for parts. I saved about $900 by doing it myself.
First, lets talk about preventative maintenance. Change the oil in the V-drive each fall, and replace with good quality 30wt oil; just shy 1 quart. When you drain the oil, look for signs of water in the oil. If there is water, the drain oil will look like chocolate milk. If you find this condition during the season, don't panic. The unit is well made, and will not fail right away. Change the oil and keep your fingers crossed that it lasts the season. Walter suggests cleaning the cooling passage each season. I agree with their recommendation. When you clean the cooling passage, keep particles from getting down the cooling system into the cooling jacket. Also, keep the bolt holes clean or the cover won't seal; vacuum if necessary. You can use the cover as a template to make your own gasket, or use my photocopy of the original. If you make your own, purchase a cheap set of punches ($2) to cut the screw holes. Make sure that you cut out the center. There is no need for sealant.
If you find problems, you might want to remove your unit and rebuild it. I noticed that the lower bearings and seals on my unit appeared in good condition, whereas the CV joints and seal looked shabby. If you are frugal, you might want to inspect the whole thing and replace only what is necessary.
Removing the unit - Disconnect the shaft from the engine. Pull the shaft out of the V-drive. It is not attached at that end. The shaft will pull right out. Unbolt the starboard mounts from the pan. There was access under the pan to get at the nuts on the starboard side. Port side had insufficient access, so I left the mount there and unbolted the unit from the mount. It weighs about 80lbs. Figure 3 hours and a couple of scraped knuckles to pull the V-drive. While it is out, this is a good opportunity to inspect, clean, and paint the pan.
Drain the oil. I suggest cleaning the unit before disassembly. It makes the job easier. It might be a good time to clean out the cooling jacket. I've found nothing that will dissolve the salt deposit inside the jacket. The case is less than 1/4 inch thick, so if yours looks more like 1/2" thick, you have a good deposit. It took at least 8 hours of chipping, sanding, brushing and cursing to get mine clean. I suggest checking for leaks before you proceed. This is done by pressurizing the cooling jacket with a bicycle pump. You need to get fittings from the hardware store to do this. If it leaks air, it will leak water. If you have a water leak, you might consider replacing the case. If it doesn't leak, you might want to coat the inside with marine tex after cleaning thoroughly. I plan to paint the inside of mine too to facilitate cleaning. Remove, retap, and replace the drain plugs in the jacket as necessary. You need a special pipe tap.
Disassemble according to the instructions in the service manual. If you want a copy, send me a self-address and stamped 9x12 envelope (6 stamps). Two of the studs had to be remove to get a wrench on the CV-Joint cover. The nuts holding the bottom cover on were difficult too. You'll need sprocket wrenches to unbolt the shafts. They not are available anyplace on the planet that I can find. You could possibly borrow mine, or fashion your own from sockets using a grinder. It took me about 2 hours to grind down a pair of sockets to fit. Take careful notes when you disassemble the V-drive. The service manual is not accurate depicting parts. I suspect that the bearings changed after they printed up the service manual. Photos help.
Resist the temptation to use a hammer to remove or replace bearings and shafts. The bearings don't like shock loads. You need a press and possibly a puller. I brought the top shaft and drive shaft to my mechanic to have him replace the CV joints. He also pressed the shafts back in. The input shaft seal was a bear to replace. I ended up taking it out in pieces.
Wire brush the outside of each case piece, avoiding the sealing surfaces. I took the case down to the car wash and gave it a good wash down with a power hose, inside and out, after brushing. Follow your notes and the service manual for reassembly. The shaft sprocket nuts are a bear to torque down. I don't think I actually got 160 ft-lbs on them. It is difficult to hold the wrench on while torquing that hard. Walter doesn't bother torquing. They use a spanner and crank it down (not to be confused with the British use of the term for a crescent wrench). Don't use a chisel to remove or replace the nuts!
Paint using your choice of colors, and reinstall. The service
manual includes great instructions for aligning the unit. To my
surprise, it requires alignment of the engine shaft. A gauge is
needed which I purchased from Walter. My next note will include
specifics about aligning the unit.
Part II: PY-424 V-Drive rebuild
This is the second and final installment on my V-drive rebuild project(I hope). This covers preventative maintenance, protecting the cooling jacket, reinstallation, and aligning the unit. My previous message covered rebuilding.
If your V-drive shows no sign of problems, I suggest leaving it alone until there is evidence of trouble; either leaking seals, vibration, or water in the oil. Change the oil in the unit each season. Inspect it for water contamination. Keep the cooling jacket clean. Keep bits of chipped deposit from finding their way to the heat exchanger. Replace the gasket with new when reassembling the unit. Insure that water doesn't leak down the dipstick.
It is important to slow the progress of corrosion inside the cooling jacket. If you can't do this, plan on replacing it when it gets to be about 20 to 25 years old. Replacement will run between $3000 and $4000.A rebuild will run about half this. If corrosion has progressed too far, it may not be possible to rebuild. I don't have a definitive answer on how to slow the process of corrosion. I chose to coat mine with marine tex followed by a liberal coat of tin based bottom paint. I cleaned the cooling jacket on my unit down to bare clean metal. The inside gets covered with a deposit that can best be described as concrete. I believe that it is composed of iron oxide and salt. The cast iron case doesn't dissolve in salt water. It undergoes some kind of metamorphosis where it is transformed into a porous yet tenacious compound. My goal was to slow or stop this disease before the jacket rusted completely through. I suppose that it would be possible to work on the cooling jacket without removing it, but you'd end up spending hours laying on the floor working on the unit. This sounds very uncomfortable.
I tried all kinds of cleaning solutions, both acid and alkaline. Tried heat and wire brushes and even sandblasting. Nothing seems to remove the deposit except a sharp chisel and elbow grease. It took several hours of tedious work to chip out the rusted bits of metal from my cooling jacket. I then wire brushed it clean and wiped it down with denatured alcohol. I applied an even coating of marine tex to the entire surface. I don't recommend coating the cooling jacket unless you do a pretty good job removing the rust buildup. I don't think the marine tex will adhere to a rusted surface. After hardening, I painted the inside with two coats of bottom paint. I still have a few quarts of tin based micron-22. The tin may add some protection against corrosion.The purpose for coating the inside with marine tex is to cover the metal with a durable barrier to water. My case doesn't leak, so there was no need to patch it. Marine Tex is reputed to be strong enough to patch the unit even if it leaks. It is not hard enough to stand up to the kind of work required to remove deposits. The bottom paint is applied over the marine tex to prevent any deposit from adhering to the inside surface.
As noted earlier, the two drain plugs in the cooling jacket were hollow casts made from cast iron. The entire inside surface of the cooling jacket lost about 1/8 inch of material during 20 years of exposure to salt water. If left alone, this 1/8 inch of metal would morph into an inch or more of concrete. In time, it would completely fill the cooling channel. Since the drain plug walls were less than 1/8 inch thick, they had completely rusted through. I replaced one drain plug with solid cast iron plug; the other with a bronze plug with zinc anode. The zinc was too long, so I cut it in half. I have mixed feelings about the zinc. If the zinc breaks, pieces will find their way into the seawater pump. This could damage the pump. I believe that this should not be a problem if the zinc is replaced faithfully each year. If you aren't meticulous enough to replace the plug each year, I suggest omitting the zinc. Damage to the raw-water pump could result if a piece breaks off and finds its way to the pump.
I had a couple of questions from Quent Kinderman about the possibility of replacing the raw water cooling system on the v-drive with an oil cooler. I suppose you could add an external oil cooler using a small generic heat exchanger. The same V-drive is available with an oil pump. It normally circulates the oil through a cooling coil that is housed inside the cooling jacket. The pump could likely be retrofitted to the existing unit. I suspect that you wouldn't even need to remove the unit. It bolts on to the end of the input drive shaft. You'd need a different cover plate (items 3SP, 13(3G), 42T, 42A, 13(42G) 42B, 43S). You could then add your own hoses and heat exchanger. I hadn't thought of doing this, but I see no reason that it wouldn't work. When the cases get too old to repair, it might be more economical to retrofit an oil cooler than replace the cases. An electronic oil pump might be less expensive than the mechanical one, but less reliable.
Replacing the assembly is the reverse of the removal process. It is awkward, and can best be done by two people; one aligning the drive shaft while the second person aligns the v-drive. Once in position, loosely connect the mounting screws to the mounting flanges. There are two adjustments. The whole mounting flange must be twisted left or right to align the unit in the horizontal plane. Since the port side mounting nuts are not accessible under the pan, pray that this adjustment is not necessary. Some minor adjustment can be made without moving the flanges. I think Pearson adjusted these before the interior was installed.
There are two vertical alignment screws on each side of the housing. I strongly suggest replacing these with stainless if you haven't already done so. These allow the unit to be raised or lowered or tipped forward or back. Adjust these until the face of the shaft coupling is flush with the v-drive coupling. Also adjust them so that the height of the v-drive is the same as the shaft coupling. An exact match is not necessary at this time. If you get it to within .015 or so, this would be close enough. Use a feeler gauge to measure the clearance around the shaft; both bottom and top, port and starboard. You'll need a hand mirror. The difference should be within .015. Make sure that all four screws are in contact with the mounting flange. Bolt the shaft to the v-drive and tighten everything down. Once the boat is launched, you will do the final adjustment.
Once the boat is in the water and has had a chance to sit for a while, the boat will change shape slightly. I don't know how long it should sit, but I suggest leaving it for a day. There is no point in doing a fine adjustment on the hard. The book says to loosen the flange bolts and measure the clearance for a tolerance of .003". I have an easier suggestion. Loosen the forward two vertical adjustment screws and the four 3/4" side mounting nuts. The unit is now sitting on the two aft adjustment screws. Leave these where they were when you did your previous adjustment. By hand, rotate the shaft a couple of times. The V-drive should align itself in the vertical position. Tighten everything back down. Take it out for a test run and see if it vibrates under load. If not, you're done.
If it vibrates, you may have a more difficult problem such as a bent flange. At least one owner was able to shim a bent flange, but this may not be easy. You can try to do a hand alignment using feeler gauges, or call a mechanic to help with this final adjustment.
Richard Carter - #47
My notes below regarding a quick method of alignment need to be updated. I've found that this method isn't good enough. It works for a rough alignment before the boat is launched, but you need to be very careful to align it precisely with feeler gauges after the boat settles in the water.
Another lesson I've learned since doing this job is that the bolts provided by Walter for connecting the propeller flange to the output flange are very difficult to work with. You can't get a box wrench on them because there is insufficient clearance. Using an open end wrench invites scraped knuckles and a trip to the bilge to retrieve them when they are dropped. I replaced mine with case hardened socket head screws from the local hardware store, and find that working on the unit is much easier. You still have to use the walter lock-washers. Regular washers are too wide and will cut the case. Walter doesn't sell these washers.They are only available when purchased as a set with their bolts.
In order to get at the socket heads, you need special allen wrench keys with round heads. The round head makes it possible to access the screw when there is mechanical interference that requires that you insert the key at an angle. Keys such as this are available from many retailers including Sears. The round head is machined on the long end of the hex key. This leaves you with the short end for leverage. You need something to get better leverage on the screw. I found that a seven-in-one screwdriver sold by Walmart has just the right size shaft to accept the hex key. When you remove the screwdriver bit, the shaft doubles as a socket. It also works great for tightening hose clamps.
As noted in an earlier message this week, the mounting screws used to attach the v-drive to the pan must be fine thread fasteners. Otherwise, vibration will cause the screws to loosen. I used 3/8x24 1.5" stainless with nylon insert lock nut, lock washers, and flat washers.
I found that the output flange on my v-drive is slightly warped. I recommend checking this with a dial gauge when the unit is on a bench. If it turns out to be warped, it is very difficult to align. I believe that Walter will reface the shaft.
Rich Carter