OK, it's finally finished. My progress was delayed by a drill press saga for another time, but I was able to borrow a buddy's and that part of the job (modifying the fore/aft factory seat rails) was a breeze.
The job is done, but not without a pound of sweat and several frustrating aspects that are worth mentioning for the sake of those who might try to "retro-fit" this piece of hardware, as I did.
1. The side-slide bottom plate is supplied with six goofy 1/8" thick, 2" diameter nylon washers on its bottom that are held in place by some inadequate adhesive and promptly fall off when you stare at them. I originally thought they must be used to allow the rails to slide without rubbing on the carpet, etc. But after I sized up the situation on my particular boat, I could not come up with any valid engineering reason why these things should be used. All they will do is raise the assembly yet another 1/8" off the floor and create a catch-all space under the side slide to lose your ATM card in, collect dirt, etc. It's a much more solid install if you just mount the side-slide bottom to the boat floor, drill & tap the holes and crank that baby down with the six 1/4-20's and some red locktite.
But uh-oh, guess what, when you torque the side slide bracket to the floor it "tweaks" it ever so slightly, making it extremely difficult to get the moving portion on (side slide horizontal rails with fore/aft bracket bolted to it). Maybe that's why the nylon washers are supplied. Anyway, after a sea of sweat and a lot of lithium grease I was able to get the assembly on the rails--although it wouldn't move side to side--so I got out my rubber mallet and pounded the thing to the right and to the left about a dozen times and lo and behold, she was "broken in" and slid great. Best of all, there was no rocking or free-play in the side-slide itself, owing to the tensioned interference fit.
After this process was complete, I discovered the following:
2. The stainless hardware as supplied by the factory (1" long SS countersunk 1/4-20's) are TOO LONG for the use they were supplied for--attaching the fore/aft slider to the side-slide rails. If you use them, they bottom out in the side-slide channels and lock the whole assembly in place. The correct screws are 7/8" long (but just try and find these at your local ACE, forget it). So going with plan B, I used a Dremel cutting wheel to knock off 1/8" on the ends of the bolts, after they had been installed with red locktite. This required sliding the whole assembly off the side-slide bottom plate, taking it into the shop, and despite masking procedures, getting stainless filings and cutting wheel residue all over the insides of both sets of rails and into the grease. More B-12 chemtool, compressed air, then more lithium grease.
Allison uses a nylock locknut at the ends of the two of these bolts, diagonally opposed, to act as stops for the side-slide against two allen head screws that are factory-installed. It was necessary to remove one of these to reduce the "Chinese puzzle" aspect of putting this thing together, i.e. you can't put THIS nut on if THAT rail is in place and you can't have THAT rail in place if you want to slide the fore-aft rails on....
By the time I was done (the first pass) I had taken nearly everything apart at least once, and unlike the factory, had used 271 red locktite to keep all the screws immobilized for life.
Proud of my final triumph over the laws of physics and satisfied that all the math I had done had indeed actually resulted in the seat being EXACTLY where it was from the factory in the first place, I paused to bask in my victory.
It was then that I noticed:
3. The seat fore-aft sliders, painstakingly aligned perfectly in parallel, were aligned SO well and slid SO easily that they allowed the seat to "rock" front-to-back about 1/2" at the top of the seat. I sat in the boat and felt the new Allison rocking chair. At first I was in denial, and figured it would be OK. But after stewing upon it all through my daughter's little league game, I knew what had to be done.
Returning home with a vengeance, I disassembled the seat and slid the assembly off AGAIN before the 271 had a chance to fully take a set.
I removed the fore-aft sliders, and after much inspection, determined that the engineering specifications for these pieces were defective and allowed for too much "slop" that allowed the seat to rock. The solution: Each rail extrusion was placed into my giant vise at the proper angle to cold forge 1" dimples into the bottoms of the rail channels. These took up the slack to almost nil and still allowed the rails to slide, just not like a bolt action 30-ought-six as before. More B-12 chemtool, more lithium grease, back to the boat.
4. Went back together and now she's the cat's pajamas, boys. Slides easily fore/aft and side to side, at every extreme and in the middle NO slop, NO rocking, your butt feels at one with the boat bottom even better than the original rickety fore-aft slide that was from 1998. Better still, I can detect no difference whatsoever in the vertical heighth increase (theoretically 1/4" higher than before). This might be because I cranked the side-slide bottom real tight into the carpet, or it might just mean the 1/4" vertical offset is imperceptible. Either way, it's golden.
Sorry for the long post, but those who don't care don't have to read it. And for those contemplating this job, hope it helps you before you start.
The job is done, but not without a pound of sweat and several frustrating aspects that are worth mentioning for the sake of those who might try to "retro-fit" this piece of hardware, as I did.
1. The side-slide bottom plate is supplied with six goofy 1/8" thick, 2" diameter nylon washers on its bottom that are held in place by some inadequate adhesive and promptly fall off when you stare at them. I originally thought they must be used to allow the rails to slide without rubbing on the carpet, etc. But after I sized up the situation on my particular boat, I could not come up with any valid engineering reason why these things should be used. All they will do is raise the assembly yet another 1/8" off the floor and create a catch-all space under the side slide to lose your ATM card in, collect dirt, etc. It's a much more solid install if you just mount the side-slide bottom to the boat floor, drill & tap the holes and crank that baby down with the six 1/4-20's and some red locktite.
But uh-oh, guess what, when you torque the side slide bracket to the floor it "tweaks" it ever so slightly, making it extremely difficult to get the moving portion on (side slide horizontal rails with fore/aft bracket bolted to it). Maybe that's why the nylon washers are supplied. Anyway, after a sea of sweat and a lot of lithium grease I was able to get the assembly on the rails--although it wouldn't move side to side--so I got out my rubber mallet and pounded the thing to the right and to the left about a dozen times and lo and behold, she was "broken in" and slid great. Best of all, there was no rocking or free-play in the side-slide itself, owing to the tensioned interference fit.
After this process was complete, I discovered the following:
2. The stainless hardware as supplied by the factory (1" long SS countersunk 1/4-20's) are TOO LONG for the use they were supplied for--attaching the fore/aft slider to the side-slide rails. If you use them, they bottom out in the side-slide channels and lock the whole assembly in place. The correct screws are 7/8" long (but just try and find these at your local ACE, forget it). So going with plan B, I used a Dremel cutting wheel to knock off 1/8" on the ends of the bolts, after they had been installed with red locktite. This required sliding the whole assembly off the side-slide bottom plate, taking it into the shop, and despite masking procedures, getting stainless filings and cutting wheel residue all over the insides of both sets of rails and into the grease. More B-12 chemtool, compressed air, then more lithium grease.
Allison uses a nylock locknut at the ends of the two of these bolts, diagonally opposed, to act as stops for the side-slide against two allen head screws that are factory-installed. It was necessary to remove one of these to reduce the "Chinese puzzle" aspect of putting this thing together, i.e. you can't put THIS nut on if THAT rail is in place and you can't have THAT rail in place if you want to slide the fore-aft rails on....
By the time I was done (the first pass) I had taken nearly everything apart at least once, and unlike the factory, had used 271 red locktite to keep all the screws immobilized for life.
Proud of my final triumph over the laws of physics and satisfied that all the math I had done had indeed actually resulted in the seat being EXACTLY where it was from the factory in the first place, I paused to bask in my victory.
It was then that I noticed:
3. The seat fore-aft sliders, painstakingly aligned perfectly in parallel, were aligned SO well and slid SO easily that they allowed the seat to "rock" front-to-back about 1/2" at the top of the seat. I sat in the boat and felt the new Allison rocking chair. At first I was in denial, and figured it would be OK. But after stewing upon it all through my daughter's little league game, I knew what had to be done.
Returning home with a vengeance, I disassembled the seat and slid the assembly off AGAIN before the 271 had a chance to fully take a set.
I removed the fore-aft sliders, and after much inspection, determined that the engineering specifications for these pieces were defective and allowed for too much "slop" that allowed the seat to rock. The solution: Each rail extrusion was placed into my giant vise at the proper angle to cold forge 1" dimples into the bottoms of the rail channels. These took up the slack to almost nil and still allowed the rails to slide, just not like a bolt action 30-ought-six as before. More B-12 chemtool, more lithium grease, back to the boat.
4. Went back together and now she's the cat's pajamas, boys. Slides easily fore/aft and side to side, at every extreme and in the middle NO slop, NO rocking, your butt feels at one with the boat bottom even better than the original rickety fore-aft slide that was from 1998. Better still, I can detect no difference whatsoever in the vertical heighth increase (theoretically 1/4" higher than before). This might be because I cranked the side-slide bottom real tight into the carpet, or it might just mean the 1/4" vertical offset is imperceptible. Either way, it's golden.
Sorry for the long post, but those who don't care don't have to read it. And for those contemplating this job, hope it helps you before you start.
