'73 MC I/O Gimbal ring removal issue

[Rainbow hunter]

I'm disassembling a 1973 gimbal and ring assembly to repair the limit switch and fix a broken screw holding the limit switch actuator plate in place. The Allen head cross bolt that intersects the upper swivel pin was frozen. Tried many things to free it up to no avail. Finally decided to drill it out. Broke one small bit deep inside while drilling a pilot hole. Drilled back from other side. Couldn't find the broken bit piece for certain. Only drilled deep enough to see the swivel shaft surface. Didn't want to go too far and damage something. I'm looking for two answers. 1. What does the swivel pin look like with regard to the cross bolt? Is there just a notch for the cross bolt to pass through, which is what I suspect, or is there a pass through hole in the pin? I've drilled,this hole out to 17/64ths and don't want to go any farther until I know if I should drill completely through this thing. Plan would be to drill out to 9/32nds, then drive out swivel pin and re-tap the bolt hole at its original 5/16ths x 18 or 24 thread.

Second question has to do with removal of the pin. Most of these upper swivel pins have a nut at the top to both secure the pin and adjust gimbal ring clearance at the top and bottom. This one doesn't have a nut. The upper pin appears to terminate In a bushing or roller bearing similar to the bottom pin. There is a quarter inch pipe plug in the case above, apparently to provide a way to drive the swivel pin out. It appears the only thing keeping the swivel pin in place is the cross bolt I'm trying to drill out, and any clearance adjustment would have to be accomplished with shim washers at the bottom swivel.

Hoping someone out there has experience with this particular gimbal set up. The whole out drive assembly is original to the boat and has serial numbers that correspond with its original year of manufacture. The out drive has the loop hole on the top and ribs on the sides or the upper housing which indicates it is an early R unit I believe. Hope somebody has some answers. Thanks guys.

Rainbow Hunter

 

[Bt Doctur]

manual 1 is needed, you need to remove the steering arm bolt first
considering the switch is almost impossible to get , just leave it alone.

 

[alldodge]

Have a look here
http://www.mercruiserparts.com/Show...bdesc=GIMBAL+RING+ASSEMBLY+AND+STEERING+LEVER

In the link above it shows item 28 as a nut

 

[Rainbow hunter]

I have the same illustration and parts list. It is a conglomeration of all parts used on several different versions of the gimbal ring. Same goes for the gimbal housing illustration and most of the other illustrations in this out drive group. I'm telling you, there is no nut at the top of the shaft in the gimbal ring I am currently working on. I have worked on several of these over the years and all had the nut you had to loosen with hammer and punch unless you removed the gimbal housing from the boat. I have already removed the steering arm bolt and it is free. This assembly is on my work bench, not on the boat, so I have clear access to the innards of the gimbal housing. Interestingly, I have both the Seloc and Mercruiser shop manuals. Both have a picture of the Gimbal ring with cross bolt (#33 in the illustration), but the text says nothing about removing it. According to the book, you remove the upper swivel shaft nut and steering arm and then use a slide hammer connected to the pipe threads in the bottom of the swivel pin to pull the pin out. Unfortunately, the paragraph about removing the cross bolt is missing and there are no pictures of the swivel shaft after removal nor in the assembly section that shed any light on the matter. If anybody has a picture in a different manual that shows the swivel shaft clearly, I'd sure like to see it. My Mercruiser manual is very old.

 

[Rainbow hunter]

I believe I have finally solved this issue. And thanks to those of you who provided food for thought. I finally came across a poorly reproduced picture of the top of a removed gimbal ring, and with a magnifying glass I could readily make out the slot in the splines that bolt 33 in the illustrations passes through. Bolt 33 keeps the swivel shaft splines and the gimbal ring splines meshed and locked. Later versions had a split down through the splined portion of the gimbal ring which were locked up with two bolts, one on either side of the swivel shaft and bolt 33 was not used. Note the illustration does not show the bolts used on late Alpha One and up gimbal rings. There is a later set of illustrations under Mercruiser parts that shows those bolts and the split ring version which uses the top nut on the swivel shaft. The confusion lies in the fact that some earlier versions did use the top nut and had no cross bolt. The cross bolt was an early attempt at relieving stress on the splines which otherwise would eventually fail. Even the two bolt system caused some problems, hence the eventual migration to the square swivel shaft. Good maintenance is the answer to longevity with the splined systems.

 

[alldodge]

Glad you figured it out and thanks for the update :thumb: