changing drive belts. 1983 300 Turbo - PeachParts Mercedes-Benz Forum

brownrice78 · #1 09-13-2009, 04:42 PM

Hello all. Got around to changing out the drive belts(83' 300 Turbo) and ran into a novice problem. I have never changed belts before, so go easy on me. I started at the power steering pump and ended up taking out 2 bolts so that the belt could be taken off easily. I then processed to the AC compressor and loosened everything(3 bolts and adjusting nut) and the belt is loose but not loose enough to really take the belt off. That's where I'm currently at.

Do I have to take out bolts to get the belt off? Is there a procedure to taking off a loose belt? A procedure to putting it on? I doubt most people change out the belts the way I got the power steering belt off. Any help would be great, thanks!

aaa · #2 09-13-2009, 05:53 PM

I know for sure that the steering and alternator belts don't need bolt removal, there're adjustment bolts to use after you only loosen the other bolts. I'd guess it's the same for the AC, but last time it gave me a hard time I just cut it since it didn't work on that car anyways.

brownrice78 · #3 09-13-2009, 09:30 PM

thanks aaa. Fortunately, I still have AC, so that isn't an option

come on guys, I know you have changed belts before??

johninva · #4 09-13-2009, 09:44 PM

i am almost certain no bolts have to come out on any of the accessories. if the ac belt isnt loose enought to take off, it isnt fully adjusted out or the compressor is caught up on something, like grimey mess.

Junkman · #5 09-13-2009, 09:54 PM

There are 3 bolts on the back of the compressor that need to be loosened in addition to the adjuster (tensioning) bolt. If the compressor can't be loosened enough to easily slide the belt on: install belt completely on the compressor pulley and partially (the bottom half) on the crankshaft pulley. Now turn the engine clockwise as you look from the front. Use a socket on the alternator pulley or the crankshaft pulley to turn the engine. Edit: belt can be removed by prying the bottom of the belt out and rotating the engine. Always rotate in direction that engine normally turns when running. It works the same way a bicycle changes gears.

Cr from Texas · #6 09-13-2009, 10:23 PM

Quote:

Originally Posted by Junkman

There are 3 bolts on the back of the compressor that need to be loosened in addition to the adjuster (tensioning) bolt. If the compressor can't be loosened enough to easily slide the belt on: install belt completely on the compressor pulley and partially (the bottom half) on the crankshaft pulley. Now turn the engine clockwise as you look from the front. Use a socket on the alternator pulley or the crankshaft pulley to turn the engine. Edit: belt can be removed by prying the bottom of the belt out and rotating the engine. Always rotate in direction that engine normally turns when running. It works the same way a bicycle changes gears.

X2, but clarify clockwise facing the engine from the front or from the driver's seat? I haven't done it for awhile but I think it's facing the engine (in working position under the hood).

brownrice78 · #7 09-13-2009, 10:41 PM

I'll try the pry method for removing/installing. I have all 3 bolts loosened and also the 10mm adjuster for the AC . The bolts are slid over as much as they will go. I'm just surprised given that most people say the belts slide off easily with the adjuster/bolts loosened. I'm hoping that the alternator doesn't have the same gig going on also.

toomany MBZ · #8 09-14-2009, 08:54 AM

Quote:

Originally Posted by Junkman

There are 3 bolts on the back of the compressor that need to be loosened in addition to the adjuster (tensioning) bolt. If the compressor can't be loosened enough to easily slide the belt on: install belt completely on the compressor pulley and partially (the bottom half) on the crankshaft pulley. Now turn the engine clockwise as you look from the front. Use a socket on the alternator pulley or the crankshaft pulley to turn the engine. Edit: belt can be removed by prying the bottom of the belt out and rotating the engine. Always rotate in direction that engine normally turns when running. It works the same way a bicycle changes gears.

Yep.
The belt may be the wrong size and the PO worked it on as above. So you may end up cutting it off, but first check the size, it should be printed on the outside of the belt. My manual states 12.5 x 925.

John Schroader · #9 09-14-2009, 09:12 AM

Quote:

Originally Posted by brownrice78

thanks aaa. Fortunately, I still have AC, so that isn't an option

come on guys, I know you have changed belts before??

What timing. I just changed all the belts on my wife's '83 300 SD yesterday. But had to put on a new alternator, so it came off anyway. As for the others, you can loosen the mounting bolts and then loosen the adjustor bolts. No need to remove anything. The way I learned this is by taking them off and then realizing that it was not required. I'm at work and cannot go pop the hood right now, so cannot give you a blow by blow description. If you haven't gotten the job done by evening, I'll take some pictures and walk you through it. Good luck.

brownrice78 · #10 09-14-2009, 10:56 AM

Quote:

Originally Posted by John Schroader

What timing. I just changed all the belts on my wife's '83 300 SD yesterday. But had to put on a new alternator, so it came off anyway. As for the others, you can loosen the mounting bolts and then loosen the adjustor bolts. No need to remove anything. The way I learned this is by taking them off and then realizing that it was not required. I'm at work and cannot go pop the hood right now, so cannot give you a blow by blow description. If you haven't gotten the job done by evening, I'll take some pictures and walk you through it. Good luck.

Thanks a bunch John. I had to put everything together again and try it out again later this week. I had no problem getting the mounts loose and moved. The belts had major slack on them, but not enough for an easy taking off and putting on. I think they are the same size. The only difference is the new ones have grooves in them(conti), the older ones have a single groove.

vstech · #11 09-14-2009, 11:55 AM

the a/c has a bracket that holds the freon lines tight. you need to remove that bolt on some cars to get the compressor to move enough to get the belt off. DO NOT TAKE THE BOLT OUT THAT HOLDS THE LINES TO THE COMPRESSOR!!! just the bolt that holds the bracket that holds the lines to the frame of the car.

brownrice78 · #12 09-14-2009, 02:08 PM

Quote:

Originally Posted by vstech

the a/c has a bracket that holds the freon lines tight. you need to remove that bolt on some cars to get the compressor to move enough to get the belt off. DO NOT TAKE THE BOLT OUT THAT HOLDS THE LINES TO THE COMPRESSOR!!! just the bolt that holds the bracket that holds the lines to the frame of the car.

I'll give it a look. I remember seeing a bracket while i was down there. I don't think it was in the way or holding back the AC though.

rrgrassi · #13 09-14-2009, 02:36 PM

You spin the crank clockwise while facing the engine. It would appear to spin counter clockwise from the driver's seat.

brownrice78 · #14 09-20-2009, 10:58 PM

Quote:

Originally Posted by Junkman

There are 3 bolts on the back of the compressor that need to be loosened in addition to the adjuster (tensioning) bolt. If the compressor can't be loosened enough to easily slide the belt on: install belt completely on the compressor pulley and partially (the bottom half) on the crankshaft pulley. Now turn the engine clockwise as you look from the front. Use a socket on the alternator pulley or the crankshaft pulley to turn the engine. Edit: belt can be removed by prying the bottom of the belt out and rotating the engine. Always rotate in direction that engine normally turns when running. It works the same way a bicycle changes gears.

Wanted to resurrect this thread to let you guys know that I followed junkman's advice and WOW! That was easy enough. I guess most people presume that you already know that bit of info

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