MC-1: Drive shaft bellows pops off bell housing when installing outdrive

[998cc]

I am really confounded by this issue. The first time this happened, I assumed there was an issue with the bellows install. I took it all apart again, cleaned all the parts, glued, etc., etc., and reassembled. The second time, there is no question the bellows was on right.

Drive: 1972 MC-1 Serial #3392031 Drive and bellows have no locating groove.
Engine: GM 250 L6


Conditions: The boat is blocked up so the drive is level. When installing the outdrive, I line the driveshaft up with the gimbal bearing and slide the shaft through. It stops just before the spigot of the drive housing enters the bell housing. I tap a remote starter switch to line up the splines in the engine coupler. It just engages the coupler, slides in a little farther and stops. The drive will not move any farther into the bell housing without using force; something is hooking onto the bellows and sliding it off while the drive is being further inserted. The only thing in there are the U-joints, but being lined up with the coupler, is it possible the U-joint is dragging the bellows off of the bell housing??

Any ideas??

 

[thumpar]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

Not sure how the bellows are coming off. If they are glued even without the clamp they are a pain to get off. Don't use the starter to line the spines. Lock the drive in forward and turn the prop to make the drive shaft splines match the coupler.

 

[Bt Doctur]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

1 most likely a engine alignment issue
2 when properly glued on, they dont just come off.
3 must be in fwd gear to install drive.

 

[998cc]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

1 most likely a engine alignment issue
2 when properly glued on, they dont just come off.
3 must be in fwd gear to install drive.

I did go through the alignment drill after replacing the front engine mount. I suppose that could still be a factor.
It takes a bit of force to push it off, and it is being pushed. The glue is dong its job; the bellows was fully on the bell housing spigot, and the clamp was tight.
Drive was in forward gear, but shift shafts not yet engaged when bellows is starting to move.

 

[thumpar]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

Are you letting the glue set up before installing? There should be nothing touching the bellows when putting the drive back on.

 

[998cc]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

Are you letting the glue set up before installing? There should be nothing touching the bellows when putting the drive back on.

Yes, the glue is set before reassembling the parts. I am sure it is not a glue or clamp issue.

 

[thumpar]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

The only thing I can think of other than that is that the gimble bearing is out of wack and letting the u-joints drag on the bellows. The only thing in there is the drive shaft and joints.

 

[998cc]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

The only thing I can think of other than that is that the gimble bearing is out of wack and letting the u-joints drag on the bellows. The only thing in there is the drive shaft and joints.

Agreed. The U-joints. The bearing is sweet. It has to be alignment. I thought I did it right and got it to the point where turning one flat of the nut made a difference in the "read" on the tool, ease of insertion, etc..

 

[84EdH]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

I have read there are two different yoke lengths with certain drives. Was yours changed since last successful install? If you need short version and long one was installed maybe it could buckle at the joint and catch the bellows? Or, take bellows off and try a dry run of drive install and you can see what is catching.

edit: I think the inline 6 engine in your year used an 8 inch yoke. The other common length is 9.5 inch. You can measure and see which length you have. hope this helps.

 

[998cc]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

I have read there are two different yoke lengths with certain drives. Was yours changed since last successful install? If you need short version and long one was installed maybe it could buckle at the joint and catch the bellows? Or, take bellows off and try a dry run of drive install and you can see what is catching.

edit: I think the inline 6 engine in your year used an 8 inch yoke. The other common length is 9.5 inch. You can measure and see which length you have. hope this helps.

Good thoughts; thanks. In this case, the only things different are the engine and front engine mount; the original engine mount had a crack in it. I measured the thread span of the original mount and duplicated that on the replacement mount before going through the alignment routine. Perhaps reinstalling the original mount will shed some light here.

 

[84EdH]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

I dont see how the mount matters. If you have aligned engine with alignment bar correctly, then mounts are fine. If its not aligned to smooth bar insertion, thats another story.

 

[998cc]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

I dont see how the mount matters. If you have aligned engine with alignment bar correctly, then mounts are fine. If its not aligned to smooth bar insertion, thats another story.

That's the issue I am now questioning. The alignment bar does not go in as smoothly as I would like, but adjusting either higher or lower results in a tighter fit or no fit. It could be a left to right error due to the replacement front mount instead of an up/down error. I am heading into the garage to pull the foot bolts out of the front mount and try a side to side adjustment to see if that helps.

 

[84EdH]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

two things: I never heard of an alignment being so far off that it pulled the uni joint bellows off: especially if the alignment bar goes in without a hammer. so, that may still be a second issue.

alignment is paramount and first. suspend the front of the engine, put the rear mount bolts through. with the front engine suspended (and nice and even from the middle of the engine (thermostat loop? if you have one), see where the motor mounts (attached to the engine block line up on the stringers. mark the holes, lag the mounts in, then torque your rear mounts and start alignment. set the engine down on the front mount lower nuts and start adjusting each side equal amounts up or down 1/4 turn at a time to get alignment. when you get it right, the bar will go in easily. then torque front mounts down and recheck alignment. it should stay the same. if it doesn't, one side is higher than the other. have you seen Chris's video in the sticky section?

 

[998cc]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

More good thoughts, thanks!

two things: I never heard of an alignment being so far off that it pulled the uni joint bellows off: especially if the alignment bar goes in without a hammer. so, that may still be a second issue.

That's good to know, and no hammer is required to insert the alignment bar. I also have a spare yoke/shaft from a second complete engine /outdrive; this shaft goes in very easily.

alignment is paramount and first. suspend the front of the engine, put the rear mount bolts through. with the front engine suspended (and nice and even from the middle of the engine (thermostat loop? if you have one), see where the motor mounts (attached to the engine block line up on the stringers. mark the holes, lag the mounts in, then torque your rear mounts and start alignment. set the engine down on the front mount lower nuts and start adjusting each side equal amounts up or down 1/4 turn at a time to get alignment. when you get it right, the bar will go in easily. then torque front mounts down and recheck alignment. it should stay the same. if it doesn't, one side is higher than the other. have you seen Chris's video in the sticky section?

My setup is a little different; it is a 165 inline 6 which uses a single center front engine mount. I did unbolt for the front mount and did get the alignment bar to enter a little more easily. Chris' video: I did watch it and my bar seems to require the same force as his, and the marks in the greased end are similar. I think the alignment is OK.

I just tried re-installing the out drive with the same result s before. It will not go in without some mechanical aid to apply forward pressure, so I stopped.

This is the same drive, engine plate, gimbal and bellhousing that was on the boat. The only difference is the engine; it is a slightly newer engine (5-6 years?) of the same type, a 165hp, 250ci L6. Could that difference require a different shaft length?

 

[thumpar]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

How far is it going on?

 

[84EdH]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

yeah, I forgot, the inline 6 is single mount, but same alignment stuff, except you don't have to worry about side to side balance.
I honestly don't know if the engine difference would change the yoke length, however, the older models used the shorter length, newer use the longer......I don't know what year they changed. that being said, if the yoke was too short, it would still go into the gimbal bearing and should reach the coupler, but not far enough. someone (lots of guys) will know more about this and chime in.

I would check the basics first. Check: your mounting the bellows correctly with side reliefs for the hinge area of the bell housing at 3:00 and 9:00, you have boat gear shift in full forward, you have the prop bungeed counter clockwise, and the shift shaft shoe aiming forward, you don't have grease on the yoke o rings, but just a light coat of oil.

when you put the drive shaft up to the housing and push the drive in, when (if) you feel resistance, get down under the drive and look up and see if the shift shaft shoes are mating. turn the prop a tiny bit to align splines in driveshaft to coupler (not much is needed, and you don't want to lose forward position of shift shaft) see what happens. if you have to use a lot of force, something is still wrong. I have lifted and kind of wiggled the drive to sort of unbind the unit, but great force is not needed. let me know what happens

 

[998cc]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

yeah, I forgot, the inline 6 is single mount, but same alignment stuff, except you don't have to worry about side to side balance.

I would check the basics first. Check: your mounting the bellows correctly with side reliefs for the hinge area of the bell housing at 3:00 and 9:00, you have boat gear shift in full forward, you have the prop bungeed counter clockwise, and the shift shaft shoe aiming forward, you don't have grease on the yoke o rings, but just a light coat of oil.

when you put the drive shaft up to the housing and push the drive in, when (if) you feel resistance, get down under the drive and look up and see if the shift shaft shoes are mating. turn the prop a tiny bit to align splines in driveshaft to coupler (not much is needed, and you don't want to lose forward position of shift shaft) see what happens. if you have to use a lot of force, something is still wrong. I have lifted and kind of wiggled the drive to sort of unbind the unit, but great force is not needed. let me know what happens

OK. the only thing I did differently from above was to grease the o-rings. I measured everything to determine where the clearance is lacking using the old extra shaft and found that it was not going all of the way in even though the alignment tool is. Using a hickory stick and a hammer, I tapped and drove it home, pulled, rotated and repeated several times. All the while, it was getting easier. Attempting to reinstall the drive after that, it went in right up to where there was 1/2" gap at the bellhousing. I drew it up with the bolts and the bellows are all intact. Hopefully, that was it!!

 

[84EdH]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

That sounds like old funky grease in the coupler splines maybe. Alignment bar being smooth goes in easy, but splines hang up on old grease or a bur or something that you persuaded with your hammer and stick. Still leaves the mystery of the bellows coming off? I woulld pull the drive back off and check alignment again.. better that than killing the coupler

Just to be clear did the bellows come off the gimbal housing end or the bell housing end.

 

[84EdH]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

That sounds like old funky grease in the coupler splines maybe. Alignment bar being smooth goes in easy, but splines hang up on old grease or a bur or something that you persuaded with your hammer and stick. Still leaves the mystery of the bellows coming off? I woulld pull the drive back off and check alignment again.. better that than killing the coupler

Just to be clear did the bellows come off the gimbal housing end or the bell housing end.

What the heck? Double post?

 

[998cc]

Re: MC-1: Drive shaft bellows pops off bell housing when installing outdrive

That sounds like old funky grease in the coupler splines maybe. Alignment bar being smooth goes in easy, but splines hang up on old grease or a bur or something that you persuaded with your hammer and stick. Still leaves the mystery of the bellows coming off? I woulld pull the drive back off and check alignment again.. better that than killing the coupler

Just to be clear did the bellows come off the gimbal housing end or the bell housing end.

Funky grease or a bur are definite possibilities.
The bellows came off of the bell housing end. As I remember, being my first attempt at the bellows, the glue may not have fully set before putting it together. I have the bellows drill down now--what an education. :joyous: I thonk the double U-jojnt was cockeyed when the shaft was refusing to enter the coupler. This time, there is no question about the bellows. I did check alignment again, and all seems good.

My original intent with this boat was to get it to the point it would run and test it out before sinking any real time and effort into it--but after getting and rebuilding another engine, new cables, chasing down corroded electrics, carb rebuild, new trailer wiring and lights, removal of the entire outdrive from the inside out, new water pumps for the engine and outdrive, bilge blower, bilge pump, and so on, we be well beyond that point now! I'm going to try and put'er in the water tomorrow or Sunday and see how she does.

Major thanks for all the input; I never would have thought of the shaft length, the consideration of which led to the discovery of the coupler issue.