Idler pulley bearing replacement

[Jonathan]

I need some clarification on which parts I may need.

My A/C has been low on Freon for a couple seasons now and thus isn't being used. I don't always run with an A/C belt, but earlier this season I did have one on. I thought I had it good and tight using the tensioning bolt.

At some point I realized it was getting loose but also chewed. As it turns out, one of the pulleys on the tensioner bracket is not rotating true. This may have caused the belt to start to get shredded or it may not have, but the edge of the belt had started to interfere with the edge of the tensioner bracket itself. And it was sharp enough to start shaving off tiny piece by piece of the belt. You can really make a mess that way with the black rubber dust all over as it was shredding it while the engine was running.

I took the belt off and it was still intact, but the one edge was worn down a fair bit. That's when I noticed the pulley was wobbling. I started researching and found a reference on the DMC Store page to a knowledge article mentioning the idler pulley bearing should be replaced at the first sign of problems.

So here's my question:

Before going ahead and taking the pulley apart, am I only going to (probably) need this:

105638 1 7-2-1 Idler pulley bearing $5.63 A/C pulley replacement parts

I listed out a number of other parts all as part of the bigger pulley assembly and wondered if any of these are likely to be damaged as well (from your experience):

SP10376 2 7-2-1 Circlip-internal $2.16 A/C pulley replacement parts
101463 1 7-2-1 Pulley-adjuster $32.40 A/C pulley replacement parts
105470 1 7-2-1 Pulley spindle $22.78 A/C pulley replacement parts
SP10034 1 7-2-1 Washer M12 $0.36 A/C pulley replacement parts
SP10806 1 7-2-1 Locknut M12 $1.89 A/C pulley replacement parts
106257 1 7-2-1 Spacer, idle bracket $0.71 A/C pulley replacement parts
105471 1 7-2-1 Spacer, A/C comp $6.74 A/C pulley replacement parts

I don't mind if you tell me all I will need is the $5.63 idler pulley bearing, but if I am bound to need more than that, I'd just as soon order it all at once.

Thanks.

[David T]

I need some clarification on which parts I may need.

My A/C has been low on Freon for a couple seasons now and thus isn't being used. I don't always run with an A/C belt, but earlier this season I did have one on. I thought I had it good and tight using the tensioning bolt.

At some point I realized it was getting loose but also chewed. As it turns out, one of the pulleys on the tensioner bracket is not rotating true. This may have caused the belt to start to get shredded or it may not have, but the edge of the belt had started to interfere with the edge of the tensioner bracket itself. And it was sharp enough to start shaving off tiny piece by piece of the belt. You can really make a mess that way with the black rubber dust all over as it was shredding it while the engine was running.

I took the belt off and it was still intact, but the one edge was worn down a fair bit. That's when I noticed the pulley was wobbling. I started researching and found a reference on the DMC Store page to a knowledge article mentioning the idler pulley bearing should be replaced at the first sign of problems.

So here's my question:

Before going ahead and taking the pulley apart, am I only going to (probably) need this:

105638 1 7-2-1 Idler pulley bearing $5.63 A/C pulley replacement parts

I listed out a number of other parts all as part of the bigger pulley assembly and wondered if any of these are likely to be damaged as well (from your experience):

SP10376 2 7-2-1 Circlip-internal $2.16 A/C pulley replacement parts
101463 1 7-2-1 Pulley-adjuster $32.40 A/C pulley replacement parts
105470 1 7-2-1 Pulley spindle $22.78 A/C pulley replacement parts
SP10034 1 7-2-1 Washer M12 $0.36 A/C pulley replacement parts
SP10806 1 7-2-1 Locknut M12 $1.89 A/C pulley replacement parts
106257 1 7-2-1 Spacer, idle bracket $0.71 A/C pulley replacement parts
105471 1 7-2-1 Spacer, A/C comp $6.74 A/C pulley replacement parts

I don't mind if you tell me all I will need is the $5.63 idler pulley bearing, but if I am bound to need more than that, I'd just as soon order it all at once.

Thanks.

Typically all you need is the 2 bearings and an "O" ring for the cam cover. If you were running a long time on a bad bearing you could need other parts. You won't know until you take it all apart. It is also possible someone was there before you and reassembled things incorrectly messing up the alignment. You MUST install each bolt, washer, and spacer EXACTLY or the pulleys will not be in proper alignment. Refer to the Parts Manual 7-2-1 for the proper order of the parts. If the belt is chewed up it should be replaced. Don't overtighten the belt, it shortens the life of the bearings. The "O" ring is #3 in 1-1-4

[Jonathan]

Typically all you need is the 2 bearings and an "O" ring for the cam cover. If you were running a long time on a bad bearing you could need other parts. You won't know until you take it all apart. It is also possible someone was there before you and reassembled things incorrectly messing up the alignment. You MUST install each bolt, washer, and spacer EXACTLY or the pulleys will not be in proper alignment. Refer to the Parts Manual 7-2-1 for the proper order of the parts. If the belt is chewed up it should be replaced. Don't overtighten the belt, it shortens the life of the bearings. The "O" ring is #3 in 1-1-4

Thanks David.

"2" bearings if I am doing both pulleys (I think you only need one for each pulley, right)? I only think one of the two is wobbly, but both could be replaced at the same time if necessary.

I hadn't realized I would need that o-ring. I think it is the same one as #24 on the 7-2-1 diagram?

You are likely right about only figuring out what is needed once it comes apart. Also true possibly about it not being exactly installed correctly. I had thought this was one thing on my year one list I had a shop do for me, but now can't find a reference to having bought a replacement bearing for the job. Not sure, but yea, I'll double check it all when apart and get what is missing or damaged.

I can order two bearings and the o-ring and then go from there as needed. I think the car is staying where it is for the remainder of the season so no problem that way.

[David T]

Thanks David.

"2" bearings if I am doing both pulleys (I think you only need one for each pulley, right)? I only think one of the two is wobbly, but both could be replaced at the same time if necessary.

I hadn't realized I would need that o-ring. I think it is the same one as #24 on the 7-2-1 diagram?

You are likely right about only figuring out what is needed once it comes apart. Also true possibly about it not being exactly installed correctly. I had thought this was one thing on my year one list I had a shop do for me, but now can't find a reference to having bought a replacement bearing for the job. Not sure, but yea, I'll double check it all when apart and get what is missing or damaged.

I can order two bearings and the o-ring and then go from there as needed. I think the car is staying where it is for the remainder of the season so no problem that way.

In my Parts Manual 7-2-1 only goes up to part # 22 and does not call out the "O" ring behind the cam cover. You have to go to 1-1-4 to find it. Yes, you always replace the bearings in pairs and there is one each for each pulley (# 3).

[mluder]

I'm not sure you have to replace that o ring... You will have to remove the fixing bolts that hold that plate in place as they also hold the idler pulley assembly. But, you should be able to re-use it unless it's in poor condition. I've had mine apart and back together several times with no ill effect.

+1 on paying attention to the order of install... I'm actually missing some of the spacers and cheated with some over-sized nuts in a few places. Shade tree mechanic.

[David T]

I'm not sure you have to replace that o ring... You will have to remove the fixing bolts that hold that plate in place as they also hold the idler pulley assembly. But, you should be able to re-use it unless it's in poor condition. I've had mine apart and back together several times with no ill effect.

+1 on paying attention to the order of install... I'm actually missing some of the spacers and cheated with some over-sized nuts in a few places. Shade tree mechanic.

Most of the time that cover falls off and the "O" ring plops out.It is almost always dried out and hard and won't seal well anymore. In fact, it is so common to replace that "O" ring, when you order the bearings as a kit from the Delorean venders they will include that "O" ring. Not so good to make substitutions for spacers and washers but obviously better than nothing.

[sdg3205]

I've found the O-ring usually needs a little help from his friend - sensor safe gasket maker - to ensure there are no leaks. Cant risk over torquing those bolts.

[DMC-81]

Hi there, I was just reviving this thread to ask a question:

When replacing the 2 idler pulley bearings, does the old bearing need to be pressed out of the pulley, and the spindle out of the bearing?


Thanks.

[Gfrank]

You won't need a press but you will have to tap it in/out. A socket and hammer will work fine, Have to remove the snap rings

[DMC-81]

Success! Thanks.

I used a brass drift between the spindle and the hammer to avoid damaging the spindle. Also, I removed any surface rust on the spindle shaft which helped make the spindle to bearing removal easier.