A/C Belt Replacement

[thirdmanj]

Hello again all- So as I was pulling the girl into the garage last night I notice a "frap-frap- frap"- in the engine compartment. It was the A/C belt on the fritz. I've checked it , its most definitely time to replace it. So the next question is.... a yeah, how do I do that?

[Ozzie]

See the brackets the pulleys are on? There's actually two brackets a short oval on the top and a longer one underneath it, and they both meet at a common bolt point. Each bracket then has it's own bolt at opposite ends. So that's a total of three bolts that go into the timing cover, from this bracket.

Now run your hand down the bracket, and you should find a long bolt that screws through the bottom of the bracket, and touches the side of the valve head. Some cars don't have that bolt. That bolt is what sets the tension on the belt.

Now that you've identified the applicable bolts. Loosen the three pulley bolts, don't remove them just loosen them. There are two spacers and a seal plate behind them that you want to keep in place, otherwise it just gets more complicated than it should to remount the bracket.

If you have the long bolt at the bottom of the bracket, then undo the nut that locks it in place, and start to loosen the bolt to relieve the belt tension. With the pulley bracket loose, that will relieve the tension in the belt, until you can pull it off the pulleys. If you don't have this bolt, the tension will be relieved as soon as you loosen the three front bracket bolts.

Repeat process in reverse to replace the belt. A good belt tension here is about a 1/4 to 1/2 inch deflection on the longest un-supported length of the belt, with a fingertip push. If you don't have the bolt on the bracket, you'll have to get creative to create tension while you simultaneously tighten the three front bolts - so you may want to consider replacing it if you don't have it. It comes in handy when required.

[DMCMW Dave]

Just an added note - be sure to tension the belt using that long bottom bolt with the two other bolts slightly loose. I've had to straighten a few of the lower brackets where someone has tightened up the tensioner with the other two bolts tight. All that does is bend the tensioner causing the lower pulley to go out of alignment and start eating belts.

The bracket is amazingly stiff steel so people who have bent them must really have been cranking on it.

[thirdmanj]

Thank you Ozzie! Very well written directions, it took me about 15 minutes and everything was right where you said it would be. I was very happy to have that tension bolt, I couldn't imagine doing that job without it! THANKS AGAIN!!!

[Ozzie]

Good job!

...actually when I first got my car, that tension bolt wasn't there and I had no other car to reference. Not knowing any better I had to figure out a way to adjust belt tension upon a belt replacement. I actually schemed a way, in which I could push with 2x4 on the top of the bracket, while I tightened the bolts. When I finally figured out I was missing that long tension bolt, I put it back and in and had to laugh at how easy it was doing it as intended, and retired my 2x4 for other duties.

Glad you're back on the road, with A/C.

[DeLorean03]

Good job!

...actually when I first got my car, that tension bolt wasn't there and I had no other car to reference. Not knowing any better I had to figure out a way to adjust belt tension upon a belt replacement. I actually schemed a way, in which I could push with 2x4 on the top of the bracket, while I tightened the bolts. When I finally figured out I was missing that long tension bolt, I put it back and in and had to laugh at how easy it was doing it as intended, and retired my 2x4 for other duties.

Glad you're back on the road, with A/C.

Well written Ozzie. That's the way we should be helping new people here. I think next time I replace my AC belt, I'm going to do a writeup like yours with pictures.

Question though. I'm aware of the bottom tensioning bolt, but for the A/C bracket you said there are.... 3 bolts?? I only have 2 - 11mm bolts and then a third being the tensioning bolt on the bottom of the valve head. Was just curious - 3 bolts + the tensioning bolt...?

[sean]

Tensioner bolt, then 3 bolts that go in for the pulley brackets, one shared by each bracket and one for each bracket.

[content22207]

#5939 showed up without a tensioning bolt, which presses against the aluminum timing case cover -- don't really know if that's such a good idea in the first place. It also was missing the upper idler pulley. I've logged nearly one decade and tens of thousands of miles like this no problem:
3025 3026 3027

Bill Robertson
#5939

[Ozzie]

Well written Ozzie. That's the way we should be helping new people here. I think next time I replace my AC belt, I'm going to do a writeup like yours with pictures.

Question though. I'm aware of the bottom tensioning bolt, but for the A/C bracket you said there are.... 3 bolts?? I only have 2 - 11mm bolts and then a third being the tensioning bolt on the bottom of the valve head. Was just curious - 3 bolts + the tensioning bolt...?

I dunno, I count three:
http://dmctalk.org/attachment.php?attachmentid=3029&d=1312055920
The two on the left actually do double duty and act as the bolts that hold the RH/456 cam seal. The other (#3 above) is the pivot point of the top bracket. All three need to be loosened to make the system pivot so it can collapse and release tension.

[DeLorean03]

Wow - I'm gonna have to go look at my car later and see if I have the 3rd one. I'm sure I do , but I swear I only loosened two when doing my AC belt replacement O_O...

[sean]

Wow - I'm gonna have to go look at my car later and see if I have the 3rd one. I'm sure I do , but I swear I only loosened two when doing my AC belt replacement O_O...

#3 in Ozzie's pic would not have been messed with if you just loosened the tensioner to replace the belt.

[DeLorean03]

#3 in Ozzie's pic would not have been messed with if you just loosened the tensioner to replace the belt.

Ah I see! And that's exactly why I only remember 2 ! FWIW, I do have the 3rd bolt :wrenchin:

[thirdmanj]

So I've had the belt running on the car for a little over a month now and I've noticed this one starting to fray also. Is a misalignment causing my new belt to fray? And if so, how do I fix it?

[Rich]

So I've had the belt running on the car for a little over a month now and I've noticed this one starting to fray also. Is a misalignment causing my new belt to fray? And if so, how do I fix it?

Eyeball the alignment to check that the belt is running straight. The idler pulleys only go on one way, including spacers. You DID get the bolt spacers back on beneath the idler bracket and the cam cover, right? Under #1 and #2 bolt in the photo on 30 July?

If it's all straight keep in mind that a slight bit of fraying is OK on a new belt. Carefully slice off the offending threads, then check it occasionally to make sure it stays in good shape.

Could also be a bad belt.

[Chris 16409]

So I recently installed one of those "DeLorean.com" AC belts on my car and it has already failed. As you can see from the picture, it has separated. I kind of suspected failure was coming because it started to fray. Luckily I had a belt on order from Amazon. I searched for Gates 9530, and they had them in stock, only nine bucks.

http://www.amazon.com/Gates-9530-V-Belt/dp/B000C2SHI8

I thought that was a good deal, cheaper than the auto part stores. Besides, isn't Gates supposed to be one of the best brands? I've heard of a heavy duty variant of this belt, but it seemed to cost much more.

[thirdmanj]

So I recently installed one of those "DeLorean.com" AC belts on my car and it has already failed. As you can see from the picture, it has separated. I kind of suspected failure was coming because it started to fray. Luckily I had a belt on order from Amazon. I searched for Gates 9530, and they had them in stock, only nine bucks.

http://www.amazon.com/Gates-9530-V-Belt/dp/B000C2SHI8

I thought that was a good deal, cheaper than the auto part stores. Besides, isn't Gates supposed to be one of the best brands? I've heard of a heavy duty variant of this belt, but it seemed to cost much more.

The last one and this one are both DMCH belts and are exhibiting the same type of fraying. I have trimmed off the offending fray and am continuing to monitor it. the alignment looks good and the tension looks sat as well. The one before this was done professionally at DMCFL. I followed the instructions I was given on this forum to a "T" So I guess I'll just have to wait and see if this is the "acceptable amount of fraying" or if its chronic o 1258.

[TTait]

You didn't let Steve attach a chain to your pulley, did you?

Check and make sure the pulleys don't have nicks in them, and that the belt can't rub anything else...

[jmpdmc]

Here is a link to the Gates online catalog with the heavy duty belt: http://tinyurl.com/42u84h6
I have used the heavy duty version in the past which I think I got from Grady. It was only about $5 more. This looks a little different in color but the specs are very similar.


Jeff

[Chris 16409]

You didn't let Steve attach a chain to your pulley, did you?

No, LOL!


Check and make sure the pulleys don't have nicks in them, and that the belt can't rub anything else...

The pulleys and brackets are the refurbished ones that Hervey sells, so I don't think there are nicks in them. I was using my old belt just fine, but my friend Ryan needed a belt, so I gave him the old one and installed my new DMCH one. It's funny because he had a Houston belt that just failed. The only thing is that I made it too tight. I was under the impression, that you should not be able to freely spin idler pulley.

[stevedmc]

You didn't let Steve attach a chain to your pulley, did you

Hehe.

[Delorean Industries]

I have seen many cars lately with gates/dayco/dmch belts installed with one of the edges frayed. This is caused by an issue with the pulley alignment. You can tell which way the pulleys are belt by the side the belt is worn on. Also if you have a VERY loose idler bearing that is cocking the pulley under tension this can also cause the belt to ride unevenly on the pulley.

Another notable thing to check for is corrosion on any of the pulley's. Cars that have sat for a period of time develop mild scaling on the pulley grooves where the plating has either been compromised or worn off over the years. This acts like sand paper on a rubber belt.

The final failure can occur from incorrect installation of the entire pulley bracket assembly. If you have the incorrect shims installed or in the wrong locations etc you will have the same issue time and again regards of how many belts you install. It will be a dead give away if it is installed incorrectly. But the bolts are long enough to put the spacers in backwards and still seal the timing cover o ring plate.


and the final comment of the day. Always be careful installing the two bolts that thread directly into the timing cover. It is very easy to destroy the threads on the two holes. It is possibly to helicoil the threads in car with the proper tools without removing the cover, yet it is anything but fun to do. If you pull either of these bolts out and see aluminum threads on the bolts immediately repair prior to installation again. If you run the bolts back in they will back off with two results. Throwing a belt and a nasty oil leak down the front of your engine.

[mluder]

When I finally figured out I was missing that long tension bolt, I put it back and in and had to laugh at how easy it was doing it as intended, and retired my 2x4 for other duties.



Like tensionng the alternator belt? :hihi2:

[DMC5180]

The number of failing DMCH belts has been an issue for a while. No specific cause has been attributed to them. As in Bad Batch or Installation Related. I'd stick with a Gates Dayco or Goodyear and always keep a spare Alt/waterpump belt in the car. Cheap insurance. Mine is in the Spare tire well.

[sdg3205]

Wild.

Just today I noticed a fray - like a thread coming off a sweater - on my DMCH A/C belt, and I don't even have A/C! I just run it for looks. I've got brand new bearings in my idler pulleys too.

In know the spacers are right because the first time I reinstalled everything they were obviously wrong.

[Chris 16409]

Just today I noticed a fray - like a thread coming off a sweater - on my DMCH A/C belt, and I don't even have A/C!

It looks like we may have an epidemic on our hands!

[Oliver Holler]

Good job!

...actually when I first got my car, that tension bolt wasn't there and I had no other car to reference. When I finally figured out I was missing that long tension bolt, I put it back and in and had to laugh at how easy it was doing it as intended

I *USED* to have a belt tension bolt, but it must have fallen off somewhere between here and everywhere.
You don't appreciate what you have until it's gone. I should have taken note of it's length and diameter, and thread kind.
Would a kind soul please tell me the specs so's I can go down to the hardware store and pick up one? (Maybe a lock nut too!)
Thanks!
Oliver
10694

[Delorean Industries]

m8 1.25 by 100mm long.

[DMC5180]

It's M8 x 1.25 or standard coarse pitch. It's about 100 mm long and FULLY threaded. That may be difficult for you to find. Normal bolts are shanked and only the first 30 mm or so is threaded. You might get lucky though.

[Delorean Industries]

There is a trick to not loosing the bolt. Essentially it is a jam nut situation with one nut fixed to the bracket and the other loose. Replace the loose nut with a nyloc and the vibration problem goes away. Works every time here at DPI.

[Oliver Holler]

m8 1.25 by 100mm long.

Thanks, Bunches!
O.

[DMC5180]

There is a trick to not loosing the bolt. Essentially it is a jam nut situation with one nut fixed to the bracket and the other loose. Replace the loose nut with a nyloc and the vibration problem goes away. Works every time here at DPI.

Yup, good trick. When installing the nyloc nut, it helps to install the nut in the normal orientation first to help form a thread through the nylon locking feature. Then remove and reinstall the nut with the nylon feature towards the head of the bolt.

[DMCMW Dave]

Yup, good trick. When installing the nyloc nut, it helps to install the nut in the normal orientation first to help form a thread through the nylon locking feature. Then remove and reinstall the nut with the nylon feature towards the head of the bolt.

Two comments
Once the two lateral bolts that go into the head through all the brackets and spacers are tight, the adjusting bolt isn't doing anything.

I've never seen the adjusting bolt/lock nut come loose, unless someone didn't tighten the lock nut in the first place.

[Trstno1]

See the brackets the pulleys are on? There's actually two brackets a short oval on the top and a longer one underneath it, and they both meet at a common bolt point. Each bracket then has it's own bolt at opposite ends. So that's a total of three bolts that go into the timing cover, from this bracket.

Now run your hand down the bracket, and you should find a long bolt that screws through the bottom of the bracket, and touches the side of the valve head. Some cars don't have that bolt. That bolt is what sets the tension on the belt.

Now that you've identified the applicable bolts. Loosen the three pulley bolts, don't remove them just loosen them. There are two spacers and a seal plate behind them that you want to keep in place, otherwise it just gets more complicated than it should to remount the bracket.

If you have the long bolt at the bottom of the bracket, then undo the nut that locks it in place, and start to loosen the bolt to relieve the belt tension. With the pulley bracket loose, that will relieve the tension in the belt, until you can pull it off the pulleys. If you don't have this bolt, the tension will be relieved as soon as you loosen the three front bracket bolts.

Repeat process in reverse to replace the belt. A good belt tension here is about a 1/4 to 1/2 inch deflection on the longest un-supported length of the belt, with a fingertip push. If you don't have the bolt on the bracket, you'll have to get creative to create tension while you simultaneously tighten the three front bolts - so you may want to consider replacing it if you don't have it. It comes in handy when required.

I was going to remove the AC tensioner bracket to replace my noisy idler bearings. Do I have to? Hervey sells a re-conditioned bracket with new bearings and pulleys that I've had my eye on. Or is there some way to replace the bearings in the pulleys without removing the bracket? I didn't know there were spacers and a seal plate behind it.....what happens if I pull it off? Will oil go all over the place?

also, when I tighten the ac belt, should I be able to freely spin the idler pulleys? The top idler pulley seems to be much looser than than the bottom unless I tighten things up....

[David T]

I was going to remove the AC tensioner bracket to replace my noisy idler bearings. Do I have to? Hervey sells a re-conditioned bracket with new bearings and pulleys that I've had my eye on. Or is there some way to replace the bearings in the pulleys without removing the bracket? I didn't know there were spacers and a seal plate behind it.....what happens if I pull it off? Will oil go all over the place?

also, when I tighten the ac belt, should I be able to freely spin the idler pulleys? The top idler pulley seems to be much looser than than the bottom unless I tighten things up....

You do have to take it all apart. You do have to keep track of all of the spacers, washers, and stuff so you can put it all back EXACTLY as it comes apart. You need the "O" ring for the cover and yes, you do get some oil but not a lot. You can wipe it up. Use the figures in the Parts Manual 1-1-4 and 7-2-1.

[burch]

I'm actually in the process of reassembling my pulleys now. Had to replace both bearings. Having some difficulty however. In the 7-2-1 diagram, it shows the pulley mounting bracket (item 9) screws matching up to the holes in the blanking plate. The mounting bracket, however, is a bit wider than the blanking plate. Am I reading the assembly diagram wrong?

35268

[DMC5180]

Your reading it wrong. The slotted adjuster goes on the two bolts that hold the cover in place with spacers. The illustration is wrong. Item 13 bolt screws into the timing cover, not through the cover plate. The lower item 14 bolt with tall spacer goes where it shows the item 13 bolt going. The zig zag tracer line is wrong. FYI I'm referencing the illustration in the parts manual.

[burch]

That was it, thanks Dennis! All reassembled and full of A/C glory (whatever that means in 110+ heat :) )

[DMC5180]

That was it, thanks Dennis! All reassembled and full of A/C glory (whatever that means in 110+ heat :) )

👍🏻

[82DMC12]

I recently went through the same thing. The sketch in the parts manual is not correct.

[burch]

Yeah, once I heard that, it went back together really easily. Per Danny @ DMCCA, I also added some Permatex Right Stuff gasket maker around the new seal on the cover plate. No leaks! :)