580sl Fan belt replacement

[MikeyJP1980]

I’m looking for the best way to install new belt. I have spent all afternoon and have been spinning my wheels. I’m going to have the whole front end off soon. The damn hydraulic pump has chapped my rear. It seems so easy but it has proved otherwise. Any tricks or proper ways would be greatly appreciated.

 

[willie59]

Been a while since I've worked on one, but I'm thinking you don't have to remove pump. Remove bolts at shaft coupling to engine crank shaft, and I'm pretty sure coupling on pump shaft will slip toward pump just enough to open a gap and allow belt replacement.

 

[willie59]

4 bolts (item #14) mounting coupler (item #12) to engine crank shaft.

 

[MikeyJP1980]

I have already taken the coupler loose and she is a stubborn. Can’t get it to budge!

 

[willie59]

Yeah, not unusual for either rust to seize coupler on shaft, or coupler splines to get worn and not move freely on shaft. And certainly not much room to work in there. If I remember correctly, you can't fully remove the 4 bolts, but possible (once bolts are loose) you can turn pump shaft 1/8 turn (so holes no longer line up), remove the rubber bushings in coupler, and make just enough gap to slip belt in. Going on a memory that's buried in cobwebs in my head though.

 

[MikeyJP1980]

I’ve got all the bolts out. It looked like the bushings came out toward the block though. Maybe I need a bigger hammer!

 

[willie59]

Right, like I said, I'm working with a real vague memory of these things, so could be totally wrong, but seems I recall you can turn the pump coupler just a bit, so bolts are no longer indexed proper with crank shaft adapter, slip the bushings out of coupler, bolts will still be in coupler, but will now move around and provide just enough clearance to slip a new belt in.

 

[MikeyJP1980]

I hope so. Thanks so much for your help! Go Vols!!!!

 

[willie59]

LoL, yeah, let's hope they do well this year.

I'm hoping alrman spots this thread, he knows way more about these things than I do. :yup

 

[fpgm04]

I don’t know if this will help you any further, but it looks like from willie59’s diagram that your L is similar to my SK. I had to replace my fan belt a few weeks ago and took some pics. See below as to how much I was able to slide my coupler forward to allow the belt to slip though.

I hope the pic may help confirm what needs to be done to get space for the belt replacement.

The trick for me was just prying back-and-forth on both sides with a little firm persuasion.
I don’t recall removing any bushings as Willie indicated and I believe you can still see them in the pic.

I have heard of people pulling the whole pump to get more leverage, but that is certainly not a first choice.

 

[willie59]

Thanks for the pic fpg, that helps a lot, seems that coupler has to slide to fit new belt, may take wetting area with spray lube and much persuasion. Otherwise, it's move pump forward. Bummer.

 

[MikeyJP1980]

Thanks fpgm, mine looks the same. I sprayed a lot of penetrating oil on the splines before I left the job site. Maybe it will loosen up bit by tomorrow. I will hit it again in the am.

 

[alrman]

Good work willie!

Some couplings do get stuborn - keep rotating the pump coupling & keep tapping the shaft using a long drift. Use plenty of penetrating oil. Some get a result by using an air impact hammer.
Don't force the coupling too much, as they seem to 'slide' better by gently rattling a prybar between the coupling & the adapter.
Be careful not to lever against the pulley as they easily bend.

 

[bowen]

Some will suggest to just cut the old belt vs working to get it off.
If so just be sure you have the right belt ready and a space large enough to get the new one back on.
On some machines I have read where other loosened the hyd pump just enough to increase the gap for installation.

Be sure the coupling is Ok because now would be the best time to replace it if the holes around the bolts are egg shaped.

 

[melben]

If you have an air chisel, put a large blunt punch in it and get down in there and vibrate the heck out of it, soon it will slide right ahead on the splines like you wouldn't believe, wish I had discovered this 40 years ago, keep it soaked up as you do this with PB Blaster or another good penetrant, You aint gonna believe how good this works!!!!!!.

Mel

 

[TheOldMan]

Some time ago, I needed to replace the belt on my 580C. I could not get the hyd pump to move. I banged it around a little, but to no avail. I ended up using a flex-link belt, which works ok, except it never seems to stop stretching. Every 3 or 4 days, you have to remove another couple of links. PITA. Went out this AM and fired her up, and got a god awful racket. Rust had built up between bottom rad mount and the mounting crossmember,raising the rad just enough to make the fan hit. Bottom mount on this thing uses 2 captive carriage bolts, and of course couldn't get the nuts off, square shank twisting round and round. Finally was able to just tear them thru what little metal was left, and got the rad out and to the shop for rbld. Now is the time to replace that belt, with rad out of the way. I can see the bolts in the coupling, but there aint much room. Gonna pull those two bolts out of the pump mount and try to move it a little first. Wish me luck, hope I don't ruin the pump prying against it.