Volvo Penta 280 Drive Shaft Nut Clearance

[simpleur2]

1984 Volvo Penta 280

I was changing my bellows when I noticed a shim hanging out from the side of the lower bearing on the upper gear box. I took it apart to replace the shims and did so on each bearing. I used the numbers stamped on the housing to double check the shim size and measured the existing shims to make sure they were correct and they were. I replaced the shims with the same size and reassembled the gear box.

I had a question regarding the clearance between the gear box and intermediate housing so I called Volvo Penta. During that conversation the mechanic asked me if I replaced the two half round keepers in the brass washer at the bottom bearing. I told him I used the old ones because they looked good. He told me to change them, so I replaced the keepers and the brass washer.

This doesn't make sense to me but after replacing the keepers and the brass washer I lost the clearance under the vertical shaft nut at the top bearing. It originally had 11 thousandths and now there is no clearance. The keepers are solidly seated into the brass washer. The nut is sitting right on the bearing. The new brass washer is the same thickness as the old. Anyone have ideas on why the clearance was lost?

There are different nuts available that give different clearances. I went to Volvo Penta to get a different nut, but all three options go the wrong direction and would make the nut tighter. It's been like trying to climb a greased rope. Any ideas would be appreciated.

Thanks

 

[muc]

They gave you good advice on replacing that brass washer and the keepers. My guess on why you lost clearance, the brass washer was starting to bend. This allows too much clearance at the nut and will keep getting worse until the brass washer lets good and the shaft will come shooting out the top of the drive.
I don't know why you now can't get correct clearance under the nut. I'm guessing that the shimming is wrong somewhere. Is it possible someone shimmed this gearbox in the past with the bent washer?
Have you measured gear backlash and used gear dye to check the contact pattern? These are two very important steps, especially when something doesn't seem right ---- like the situation your in now.
What size nut do you have? Is it flat all the way across the face of the side of nut that faces the bearing and shaft?
You can use the nuts from a newer SX drive, they are the same and much cheaper. They come in 4 sizes 0.00mm to 0.60

 

[simpleur2]

They gave you good advice on replacing that brass washer and the keepers. My guess on why you lost clearance, the brass washer was starting to bend. This allows too much clearance at the nut and will keep getting worse until the brass washer lets good and the shaft will come shooting out the top of the drive.
I don't know why you now can't get correct clearance under the nut. I'm guessing that the shimming is wrong somewhere. Is it possible someone shimmed this gearbox in the past with the bent washer?
Have you measured gear backlash and used gear dye to check the contact pattern? These are two very important steps, especially when something doesn't seem right ---- like the situation your in now.
What size nut do you have? Is it flat all the way across the face of the side of nut that faces the bearing and shaft?
You can use the nuts from a newer SX drive, they are the same and much cheaper. They come in 4 sizes 0.00mm to 0.60

Thanks for responding,
First thing I did was calculate the shim size as outlined in the shop manual using the letters and numbers stamped on the case and etched on the gears. I checked the existing shims to see if they matched the calculation and they did so I replaced with the same sizes. I had about .010" clearance under the nut. All was good until I was urged by the Volvo Penta mechanic to change the keepers. I changed the keepers (not the thrust washer) and my clearance got tighter (.006"). I thought that was kind of tight so I checked in with Volvo again explaining how the clearance had gotten tighter. They told me the thrush washer is a common wear item and I should have changed it as well. I did, now I have new keepers and thrust washer and my clearance disappeared. The washer sits on the bearing.

I think my nut was originally a flat nut but now the inner steel ring protrudes about .003" above the brass surface (probably due to wear). This struck me as weird because all of the washer options available at Volvo would result in less clearance.

My backlash is about .010", I didn't check with gear dye. Never did that but it's probably not rocket science. Do the newer SX nuts start with the flat nut resulting in the most clearance? If so, their ranges go the same direction as the 280 nuts. That is what's bothering me the most. Everything is basically a fixed length or dimension. Only thing that can change is the shims under the bearings. Should I disregard the calculations and shim to backlash? At this point there would be nothing left to try accept turning the nut down on a lathe to get the clearance.

 

[muc]

I'm not sure what you have going on, but here are a few things I've learned at Volvo school and doing this job many times.

It's pretty rare the shims you install per the calculations are what you end up with after backlash and gear patterning.

Backlash and patterning are not optional, they must be done.

Backlash is a tough measurement on this gear box, very important that the indicator be positioned in the center of the tooth (half way between heel and toe and half way between the root and top land) and at 90° to the face of the tooth. Try taking this measurement in a few different places, it can change by .003 to .008". Big difference when you NEED .006-.010"

Get a tube of yellow gear marking compound. I've had good luck with GM #1052351 it's so much easier to see the contact. Assemble the upper without the clutch and use a piece of 1"X2"X1' wood to put pressure on the gear cups when you spin the input gear.

I've never seen a nut like you're describing. Yes the #0 nut is flat, I kept one in stock just because I didn't want to hold up a job over a $15 nut ---- never used it. Not what you want to hear, but your nut is bad and you need a new one. The nuts for the SX are one piece steel, not like yours with brass in it.

Every replacement brass washer came from Volvo as a steel washer and I would sometimes have to seat the keepers before assembly. I know you said they are seated, but I would recommend you disassemble and take the bare shaft with just the washer and keepers. Give it a good hit with a brass hammer to make sure it's fully seated.

These gear boxes are one of the harder ones to get right, took a few of them under my belt to start beating flat rate. Keep at and you'll get it right.

You have something wrong, please don't modify any parts. It probably won't end well.

Out of time for now. If this wasn't clear or I didn't answer your questions, post again and I'll try to help.

 

[simpleur2]

I'm not sure what you have going on, but here are a few things I've learned at Volvo school and doing this job many times.

It's pretty rare the shims you install per the calculations are what you end up with after backlash and gear patterning.

Backlash and patterning are not optional, they must be done.

Backlash is a tough measurement on this gear box, very important that the indicator be positioned in the center of the tooth (half way between heel and toe and half way between the root and top land) and at 90° to the face of the tooth. Try taking this measurement in a few different places, it can change by .003 to .008". Big difference when you NEED .006-.010"

Get a tube of yellow gear marking compound. I've had good luck with GM #1052351 it's so much easier to see the contact. Assemble the upper without the clutch and use a piece of 1"X2"X1' wood to put pressure on the gear cups when you spin the input gear.

I've never seen a nut like you're describing. Yes the #0 nut is flat, I kept one in stock just because I didn't want to hold up a job over a $15 nut ---- never used it. Not what you want to hear, but your nut is bad and you need a new one. The nuts for the SX are one piece steel, not like yours with brass in it.

Every replacement brass washer came from Volvo as a steel washer and I would sometimes have to seat the keepers before assembly. I know you said they are seated, but I would recommend you disassemble and take the bare shaft with just the washer and keepers. Give it a good hit with a brass hammer to make sure it's fully seated.

These gear boxes are one of the harder ones to get right, took a few of them under my belt to start beating flat rate. Keep at and you'll get it right.

You have something wrong, please don't modify any parts. It probably won't end well.

Out of time for now. If this wasn't clear or I didn't answer your questions, post again and I'll try to help.

Muc,
Something came up and took the time I needed to work on my gearbox. After a quote of $4,000 to shim the gearbox I'm doing it myself again. The only thing that's confusing me is there were no shims between the clamp ring and The upper gearbox and the parts schematic for the unit does not show shims in that location (the manual does). I have removed a shim from under the forward and reverse gear and regained some clearance under the nut. Now the backlash is too tight so in my mind I need to shim the drive gear out to gain more backlash since I can't add shims to the forward and reverse gear. Am I correct in assuming there should be shims between the clamp ring and the gearbox if needed? I don't understand why they don't show on the parts diagram. If so I will shim the drive gear out to get the proper backlash and check the pattern.

Thanks

 

[muc]

Muc,
Something came up and took the time I needed to work on my gearbox. After a quote of $4,000 to shim the gearbox I'm doing it myself again. The only thing that's confusing me is there were no shims between the clamp ring and The upper gearbox and the parts schematic for the unit does not show shims in that location (the manual does). I have removed a shim from under the forward and reverse gear and regained some clearance under the nut. Now the backlash is too tight so in my mind I need to shim the drive gear out to gain more backlash since I can't add shims to the forward and reverse gear. Am I correct in assuming there should be shims between the clamp ring and the gearbox if needed? I don't understand why they don't show on the parts diagram. If so I will shim the drive gear out to get the proper backlash and check the pattern.

Thanks

Shims go between the clamp ring and bearing box on a 280. No shims between clamp ring and upper gearbox on these. These shims show as still available in the parts lookup.
Are you sure you are working on a 280? The uppers can be mixed and matched on a lot of these drives. Are you using a crush sleeve to set the prestressing or shims on the input gear?
What manual are you using?

 

[simpleur2]

Shims go between the clamp ring and bearing box on a 280. No shims between clamp ring and upper gearbox on these. These shims show as still available in the parts lookup.
Are you sure you are working on a 280? The uppers can be mixed and matched on a lot of these drives. Are you using a crush sleeve to set the prestressing or shims on the input gear?
What manual are you using?

I'm using a Volvo Penta manual the dealer emailed me. It's titled "Workshop Manual AQUAMATIC 280, 280-DP, 285, 290, 290-DP" Volvo Penta at the bottom. The following page says Workshop Manual, Drives 280, 280-DP, 285, 290, 290-DP, SP-A, SP-C, DP-A, DP-B, DP-C.

I did find shims between the clamp ring and the gearbox. I had to take a pick and pry at the edge of the shims to get them free from the seat. The were stuck down to the surface and undetectable to the eye (dang salt water).

I haven't messed with the drive gear and the tapered bearings just changed the drive shaft seal and washer. I believe it is the crush sleeve type. Isn't the crush sleeve for bearing preload?

Now I'm going to go buy a few different sizes of shims and start working on getting the proper pattern on the gears and hopefully I don't wind up chasing my tail.

I appreciate your help and attached a couple of pictures of my upper unit. I don't know how to confirm its a 280, the cover on the back of the unit says its a 280

 

[muc]

Looks like the right manual.
If you changed the seal and washer, you had to remove the u-joint yoke and should now recheck the prestressing. Prestressing is handled one of two different ways on Volvo. Crush sleeve which isn't reusable and must be replaced if it has been crushed once before or shims under the washer you replaced.

"Shims go between the clamp ring and bearing box on a 280. No shims between clamp ring and upper gearbox on these."
This was from my memory and it's been many years since I reshimmed one of these. Looking at your photo and the manual ------ it seems that my memory is failing me ------- I WAS WRONG ----- hate it when that happens!

 

[simpleur2]

Looks like the right manual.
If you changed the seal and washer, you had to remove the u-joint yoke and should now recheck the prestressing. Prestressing is handled one of two different ways on Volvo. Crush sleeve which isn't reusable and must be replaced if it has been crushed once before or shims under the washer you replaced.

"Shims go between the clamp ring and bearing box on a 280. No shims between clamp ring and upper gearbox on these."
This was from my memory and it's been many years since I reshimmed one of these. Looking at your photo and the manual ------ it seems that my memory is failing me ------- I WAS WRONG ----- hate it when that happens!

It had shims under the washer for prestressing. And I took a pick and did find shims between the clamp ring and double bearing housing. Looking at them I would have swore there were no shims. Unfortunately I have been chasing my tail for two days trying to get a good pattern on the forward gear. Came close once but the backlash got tight (0.005") and I'm betting it will get a bit tighter once the bearings are crushed. If I add shims under the double bearings to gain lash the nut clearance is lost. Im hosed untill tomorrow, I need a couple of 1mm shims I dont have. Gonna try calculating the stamped numbers again and see where I land. Sure sucks

 

[simpleur2]

It had shims under the washer for prestressing. And I took a pick and did find shims between the clamp ring and double bearing housing. Looking at them I would have swore there were no shims. Unfortunately I have been chasing my tail for two days trying to get a good pattern on the forward gear. Came close once but the backlash got tight (0.005") and I'm betting it will get a bit tighter once the bearings are crushed. If I add shims under the double bearings to gain lash the nut clearance is lost. Im hosed untill tomorrow, I need a couple of 1mm shims I dont have. Gonna try calculating the stamped numbers again and see where I land. Sure sucks

Muc,

I've been shimming my gonads off and got a really nice pattern. Only thing is I have 0.006" backlash on the reverse gear and 0.005" on the drive gear. Tolerance in the manual calls for 0.006 - 0.010". Is it really going to explode over 0.001" ?

I can try throwing another 0.002" under the drive bearing and see what that does. I think I can spare that under the nut but don't know what's gonna happen to my pattern. I would have 0.012" under the reverse bearing and 0.014" under the drive bearing. I'll probably try that but if the pattern is bad there's the question of the 0.001" being a show stopper or not. what do you think? honest opinion, I won't blame you if it self destructs over the thousandth of an inch.

Thanks








'

 

[muc]

Muc,

I've been shimming my gonads off and got a really nice pattern. Only thing is I have 0.006" backlash on the reverse gear and 0.005" on the drive gear. Tolerance in the manual calls for 0.006 - 0.010". Is it really going to explode over 0.001" ?

I can try throwing another 0.002" under the drive bearing and see what that does. I think I can spare that under the nut but don't know what's gonna happen to my pattern. I would have 0.012" under the reverse bearing and 0.014" under the drive bearing. I'll probably try that but if the pattern is bad there's the question of the 0.001" being a show stopper or not. what do you think? honest opinion, I won't blame you if it self destructs over the thousandth of an inch.

Thanks








'

.001" isn't much ------ but we have a saying in all the drive schools I have attended. "better lose than tight"

I would recommend you keep at it. Some drives take more time them others, but getting it right is possible.

 

[simpleur2]

.001" isn't much ------ but we have a saying in all the drive schools I have attended. "better lose than tight"

I would recommend you keep at it. Some drives take more time them others, but getting it right is possible.

Think I finally have it done two months and fifty trips to the parts counter later. I am ready to install it onto the intermediate housing but I have a shimming issue. I over shimmed and installed the transmission onto the Intermediate housing in order to get a distance between the two cases and calculate the 0.004" of bearing crush the manual calls for. I calculated the distance and need the 0.05mm shim listed with all the other shims on the parts list to achieve at least 0.003" of crush. Well I drove 45 minutes to get the shims only to find out when I got home that they are a different diameter than all the other shims listed for the application and won't work (I am the king of freakish things happening to people). I contacted the Volvo Penta dealer I purchased the shims from and he confirmed the 0.05mm shim was a different diameter than the 0.10mm. 0.20mm and 0.40mm shims it was listed with. I need to wait at least a week before they will have an answer from Volvo Penta on the discrepancy.

If there is not a 0.05mm shim available that leaves me with choosing between a pre-torqued gap of under 0.002" of an inch or 0.006"+ of an inch. I surely don't want to spin a bearing due to insufficient bearing crush but having 6+ thousandths seems like alot since the manual calls for 0.004" max crush. Any advice on which way to go if there is no small shim available ?

Have no clue why the thinnest shim listed for this application is a smaller diameter than the others. Even though I have to lose another week (probably more) to get an answer, it would be nice if Volvo Penta can offer the right shim. Either way without the smaller shim will be choosing between incorrect end results. Thought I was done

Thanks


Thanks

 

[muc]

What a long strange trip it’s been. Sorry but that seems to fit here.
I have to believe the dealer just had some mismarked shims and you will be able to get the right ones.
If you can’t
If the bearing you’re shimming has been spun under load at least once—go loose. If it’s a brand new bearing—go tight.
we always crush new bearings more than used ones.

 

[simpleur2]

What a long strange trip it’s been. Sorry but that seems to fit here.
I have to believe the dealer just had some mismarked shims and you will be able to get the right ones.
If you can’t
If the bearing you’re shimming has been spun under load at least once—go loose. If it’s a brand new bearing—go tight.
we always crush new bearings more than used ones.

I'm on the West Coast. Out of curiosity I called the other Volvo Penta dealer in Florida (never know there was only two in the US) and their 0.05mm shim is a different diameter as well. Strange deal, hope they can provide the right shim.

 

[muc]

(never know there was only two in the US)

I worked for 4 different Volvo dealers here in Minnesota. Only one of them stocked all these shims. They are long gone. 2 are still in business. Have you tried the dealer locator on Volvo’s website?