New Alignment Bar Dimensions for GKN Driveshaft Assemblies?

[harringtondav]

Five year old VP SX-D coupled to a G5 VP 4.3 with 23400765 engine coupler.
I just did my first drive pull for inspection and prepping for driveshaft bellows replacement. I tried checking the alignment with my Merc bar, 1.010" spline pilot diameter. The bar wouldn't enter the splines. Hard stop at the coupler. I did some research. The Merc coupler and U joint splines are ANSI B92.1. Likely made by Rockwell like previous VP shafts. I checked DIN 5482-5480 std because the GKN assembly. Very similar 17 tooth 30 deg PA splines, but the coupler minor diameter is .001-.006" smaller than the 1.010" bar pilot diameter.
I also have a second alignment bar with a 1.0045" pilot. (long story). The bar wanted to start but didn't get past the coupler's lead in champfer.
I can take the old bar to a machine shop and have them trial and error dust the pilot down until it slip fits.
Does anyone have any knowledge/experience on this? Knowing the correct tool size would save me some time and money.
Thanks, Dave

Any insight on this?

 

[alldodge]

My understanding is all use same alignment bar, or at least I've always used the same and they work. The 1.010 is what I have

 

[harringtondav]

That was my understanding too AD. But my 1.010 bar wouldn't fit. Years ago I used it the check an OMC Cobra I was working on and it worked fine, just like it did for 25 yrs on Merc Alpha 2's.

 

[alldodge]

I would think if it doesn't fit then things have moved. Look closer at the mounts. Get the bar to go in straight, remove put grease on outer edge and slide back in, remove and check marks

 

[harringtondav]

The std bar wouldn't enter the coupler. The 1.375" gimbal bearing pilot was at least 1/2" from entering the bearing.
The smaller 1.0045" bar just started in the splines leaving even spline marks around the first 1/8" of the bar.
The DIN spline standard has the coupler's minor diameter smaller than the small bar.

 

[Lou C]

Is there any information in VPs service literature about having to use a proprietary alignment bar for their new style drive? These have been out quite a long time so you’d think it’s common knowledge by now. Did the drive slide off easy or did it seem stiff?

 

[harringtondav]

The only reference is in my VP engine shop manual under installation of the engine. It referenced a dealer/boat builder installation manual number that I can't find.
The drive jumped off easily when I pulled it.
I believe the alignment bar is probably proprietary. I've got a call into my dealer's shop to see if they have any info on the tool or the coupler pilot size.
I like the VP SX-D drive compared to the Merc Alpha 2 I had for 25 yrs. But VP has a lot of mystery meat in their parts and service that I think purposely thwarts DIY.
Their new U joint driveshaft assemblies don't offer replacement Unis. You have to buy a whole driveshaft assembly. While the drive is on the cart in my garage I'll pull a U joint and find a replacement. Merc Bravo and Sierra have ones that look like they'll fit.

 

[harringtondav]

Is there any information in VPs service literature about having to use a proprietary alignment bar for their new style drive? These have been out quite a long time so you’d think it’s common knowledge by now. Did the drive slide off easy or did it seem stiff?

Mystery solved. The service manager checked the diameter of their new alignment bar with a mic and it is 1.000".
This makes sense. I looked up the internal spline minor diameter for the DIN std and the low limit is 1.004". My Merc 1.010" bar had some clearance in the coupler when I put the bar in without the gimbal bearing installed.

 

[Lou C]

Glad it's solved! I have seen this before with Volvo, steering actuators they say can't be rebuilt (but can be depending on which seals were bad) trim rams that couldn't be rebuilt (but now they offer a kit to do so just like OMC did).