So I feel like an idiot, but I'm having a hell of a time getting the new drive belts on to my 1985 300D. Right now I'm having an issue with the AC belt. I've got the compressor swung as far as it'll go an I can't get the belt slipped on. Even tried another user's trick of leveraging with some wood- no dice.

I've been at it for a few hours and nearing the point of needing to step back before I throw something across the garage.

I can compensate with beer and pizza. Anyone in the Metro ATL area able/willing to lend a hand between tonight or any time tomorrow in Kennesaw? I have all tools needed (besides the belt tension tool) so all I'd need is maybe an hour of time and some seasoned perspective.

Thanks,

On my 300SD there are several threaded long bolts which are adjusters for the belts. Also there are bolts on the front and maybe one or two on the back of something (compressor, alternator? - do not remember - but when I installed a new AC many years back there was a bolt on the back).

Are you sure you have all the adjusters undone and you have removed the bolt in the back? At least the SD is designed so you no longer need to use a 2x4 to tighten the alternator. Much easier now than on my old '57 Chevy. Assume the 300D is designed the same way.

Not sure this helps. Are you sure your new belt is not shorter than the original?

Thanks for the response.

I have all 3 of the bolts loosened on the back of the compressor. Two from the top, one from the bottom. Should these only be loosened, or do they actually need to be removed? Per the Pelican write up, Wayne says loosen, but that's obviously not cutting it.

I can't say what the old belt was, I recently found it looking like a rat's nest when I picked this car back up from my dad after a year. They are all Conti brand belts from Pelican for this car specifically. So, it could very well be wrong,but the other 3 did match the old ones.

Well, do not remember. Seems to me like the back one needs to be removed for the thing to pivot but not sure. If the directions say otherwise, maybe they are right. Has been maybe ten years or so ago - long time. But I do not remember having any problem at all in getting the belts back on. That makes me wonder if you do not have something rotated in fully so the belt will slip on easily. Or the adjusters backed off fully. Really it is a great bit of engineering the way you can restretch the belts with the adjusters - just need a wrench and no 2x4.

On second thought, not sure how it could pivot if it has more than one bolt in it. If it has two bolts in it, it cannot pivot. Maybe slide in or out but not pivot.

I ended up loosening them until they were right where I could feel them about to come out. Managed to get all of the belts on and tightened up from there.

This job isn't hard, but I did find it to be a PITA. It'll probably be much easier the next time I do it.

Good you figured it out. And I really wanted to come over for the Pizza and beer.

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

I wish I had some old Benz buddies in the area, but alas, I only know of the indy shop down the road and he charges money to help work on cars!

Glad you got it done. What exactly helped about backing out the bolts more? I would have thought you would have needed to pivot it more but that could not be if all three bolts were still in their holes.

How tight did you get the belts? Seems to me like you look for something like a half inch movement when you press down on the installed belt.

Honestly, I couldn't say exactly what did the trick. I maxed out every bolt just to the point they were almost all the way out and got it close enough that I was eventually able to muscle the belt into place.

The belts may be a little snugger than 1/2" deflection. I read 1/4" somewhere else so that's what I went with. The AC belt may be a little snugger than necessary right now, but I'll play with that again when it's time to use it. For now, I'm just glad the job is done.

Good deal; glad you got it.

Silly question, but you did put the belt on the large pulley first, then work it over the smaller one, right?

__________________
'85 300D - federal spec, built in late 84. 85 300D Complete AC System Rebuild

The 3x 19 mm bolts just need to be loosened a few turns, not maxed out. The only one that needs to be maxed out is the 10 mm belt tension bolt, which allow you to swing the compressor all the way towards the crank pulley so you can get the old belt off and the new belt on.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

That was what I was trying to remember. You need to completely loosen the belt tensioner and then swing it in to replace the belt.