Bobcat 863 lap bar spring installation

[Bobcat99]

Hello everyone,

I'm trying to reinstall the spring for the seat lap bar. I had to take out the seat bar switch to test it, and at the time it seemed I had to remove the spring, as well (though I'm not sure if there was a way around that).

Anyway, it seems like it should be simple enough to do, but I cannot quite figure out how to recompress the spring or install it back together, and I feel as if I'm missing some trick or I'm doing something out of order.

I have a little homemade spring compressor, but it doesn't fit into the area. I also tried using the spring retaining bolt and tightening it and holding it compressed with zip ties, but they seem to loosen up.

I've been trying to install it with the seat bar switch and seat bar bolt connected first, as the seat bar arm needs to have the bushing installed first, etc.

Or should the spring go on first and then attach the yoke with the pin and retaining clip? Then deal with the seat bar bushing/switch? Are you able to pivot the arm out to install the bushing and switch, if the spring is attached first? Or is it under too much tension then?

I must be doing something wrong, so if someone could please let me know what the right way of doing this is, I'd appreciate it.

Thanks.

Joe

 

[crewchief888]

ive never had any luck using zip ties to hold those springs. i use mechanics wire, and compress the spring in a vice.

 

[Bobcat99]

Thanks for the tip, Crewchief.

I tried a variety of installation methods, always just barely missing it. I read somewhere else someone trying to drift the yoke for the spring in position and then push the pin in, but I'm worried about breaking the plastic switch behind it, should something slip on me.

Joe

 

[Bobcat99]

Okay, I got the spring and sensor back in place tonight.

I tried first to use some metal wire, but I found it kept spreading too much and so the spring wouldn't fit. Now the wire I used was some old general purpose spool I had from Home Depot, so maybe not proper mechanic's wire, and that's why it didn't work right.

But, I figured out another way, which might be helpful to some. You don't have to cage the spring, which I prefer, not to take a chance (as this one needs a lot of compression). This way, though, really requires a second person to help.

What I did was I first installed the sensor bushing and sensor onto the seat bar arm, slid it all in place and installed the 9/16" bolt (I left the smaller retaining bolt out to give a bit of play as the sensor can get bumped into a bit during the process). Next, I attached the whole spring and yoke assembly to just the seat bar arm first, so that the allen head bolt is through the seat bar bracket and threaded into the yoke that will get pinned to the mount. I threaded the bolt just enough to grab onto the yoke.

At this point, I inserted the bushing for the yoke's pin into the mount, because when you tighten the bolt later, the yoke may get in the way and you might not be able to move it to put the bushing in place.

Now, if you try to compress the spring by tightening the Allen head bolt itself, it will just bottom out through the yoke and against the seat bar mount. It will fall shy about 3/8" of lining up the yoke hole with the seat bar mount hole/bushing. So, the trick I found is to shim out the allen bolt head away from the seat bar tab, which is easy enough to do when it is barely threaded onto the yoke and there isn't much tension on the spring. I found using a 7/16" open end wrench works well, small enough to go under the bolt head and around the bolt shaft like a fork and a large enough head to shim out enough. I put the wrench in sideways through the cage of the machine, as the seat tab is bent and you can't really slide the wrench in easily from any other way.

Then, while someone holds the wrench from outside the machine to keep it from possibly slipping out, you tighten bolt, compressing the spring as far as you can go. I tried to find a vise grip or something else at first that would lock over the bolt, without gripping the bolt, but I couldn't find anything else around that would work, so I just asked for a hand and used the open ended wrench, which is actually a pretty ideal thickness to use anyway.

After tightening the bolt as far I as could, the yoke is fairly close to alignment, maybe 1/8" or so off. So, with the open ended wrench still in position, shimming out the bolt against the retaining tab, I then used a large Phillip's head screw driver (3/16" or so shaft) to pry and drift the yoke and seat mount bushing in alignment (again done from outside of the machine and through the cage). It may go without saying, but you need the screwdriver in as deep into the bushing as possible, so that it doesn't slip out on you as you pry, while leaving enough room to be able to insert the pin through the yoke and start it into the bushing, which the second person does from inside the machine. Then, once started, you just pop the pin through as the screwdriver is removed and install the retaining clip.

I tried a variety of combinations, but this way was pretty easy, albeit with a second person's help. There was no real strenuous or dangerous prying taking place, in attempts to compress the spring and get the yoke into alignment. Most of the extra compression needed is obtained by using the open ended wrench as the first spacer and tightening the bolt as far as it can go in place, and the rest is done with the long screwdriver or any drift and a bit of leverage at the end.

Short of tying the spring with a better wire, I found this to be a pretty good way of getting it back together. If anyone else has any other methods, I'd like to hear it.

Joe

 

[Bobcat99]

Oh, and I forgot to add for anyone else doing this, that after you have installed the pin and retaining clip for the yoke, you have to loosen the allen bolt and return the spring tension to the same amount as the other side. For a reference, I just checked the distance the bolt protrudes through the yoke, which should be about 3/16" or 3 threads on the bolt.

Joe

 

[Bing Schmitt]

Joe's method works!!! 2012 Bobcat S-300 with glass, I called the service, they told me to raise the cab and remove the entire lap bar and mounts from the cab. That's about 2-3 hours. So I came on here to see what I could find out. Saved a bunch of time. I used the open end of a 7/16 tubing wrench inserted from below the lap bar under the head of the allen bolt in the pocket(it was at an angle). A little lube might help between the bolt head and wrench. It threaded the clevis into complete alignment with the hole in the mount.