Michael S

Buy a A/C bypass pulley for a 1995 Chevy 1500 with a 350!

I came across this little fix by accident. I was going to fabricate my own and just wanted the pulley. The Dorman AC bypass pulley for early 90's model Chevy trucks is only $35, where I've seen Corvette websites sell pulleys by themselves for $85!

Is it a direct bolt in Smog pump bypass pulley? NO, you will have to make two minor mods and cut two spacers for it to fit....but since there are none offered by the aftermarket industry due to the one year nature of our 84's, this is as close as you can get in my opinion.

Since I work at a place that has a machine shop, I had plans to build a nice custom piece out of Stainless Steel, but this actually works better (IMO) because as it's lighter. Plus, just about anybody can do this with simple garage tools.

First get a Dorman 34152 A/C bypass pulley.


Now if you look closely at the picture you'll see the bolt holes are different sizes. You'll need to drill out the smaller one to match the larger one. Sorry, my drill bit had too much shaft wear to read what size it was and I didn't think to use my dial caliper to check it. It just fit and worked. If you don't have one that fits it, and no a way to measure the hole, just take it with you and find one that fits the larger hole.

Secondly you'll need to cut back a small section of the "riser" leading from the bolt mount to the pulley. so your PS pump/ alternator bracket will clear.


You'll then need two spacers so you can mount the pulley in place.
the top one needs to be 13/16" and the bottom one 3/4".
If someone doesn't have access to any materials to make them or find anything to buy, let me know. I'll cut you a couple and send them to you for cost of shipping.

I know some guys just take them off and run a much shorter belt, but I didn't like the look of the area without something there or the idea of the belt having that long of a run without support.

So before....


and After.....


I did end up having to turn the top bolt around as it was rubbing on the air cleaner housing.




Pretty simple fix and relatively clean looking.
Much better than a $175 bracket like the 85 and up uses!
***New belt size is 87 inches***

Hope this helps out any of my fellow 84 CFI owners here.

GQ-ROD

Great post !

1985 Corvette

Sure beats the $175 Corvette piece. Corvette Tax, indeed....

Michael S

I didn't think about it, but if the bolt pattern on the 1985 and up are the same, then it could be used on them too.

pezter22

Very cool.

I ordered one from Jegs last night. I gutted my AIR pump last year and left the unit installed. I like this much better and will start planning my install.

C4.R

Hi, Great modification! Which belt do you use for this? The only 87" belt I can find is slightly smaller in width then the standard width (0.828 standard width, as used for the removal of the pump without the roller: https://www.summitracing.com/int/par...0850/overview/), the 87" belt I found is this one: https://www.summitracing.com/int/par...make/chevrolet which is 0813inch wide.

Please advise, as I prefer this modification over the 85" belt without the roller. Thank you

Kind regards,
Aernoudt

Michael S

I didn't save the part number, but the way I found it was trial and error. I went to my local Autozone parts store, where I had a guy I had been working with during the time I owned this car. He would go back into the back and get me a shorter belt. If it was too short, we got a longer belt. After trying out 3 belts, we found one that the 87" worked perfect.
What you have to do is get the part number of the original belt. Let's use the AC Delco for example. 6K882. it has an "effective length of 88.2 inches. So find whatever belt manufacturer you're looking to use and look for the length numbers in the part number. Then look for something, close to 87.
Hope that helps you on your quest.

C4.R

Thanks; was hoping for the part number as the trial and error is not as easy over here as in the US, as every part needs to be ordered and shipped from the USA by mail to the Netherlands

Michael S

That's what I was afraid off. I'll say this. What brands of belts can you get? For sizing proposes it's a 6 rib belt.
Here is a 6 rib, micro v-belt that's 87 1/4" long.

C4.R

Thanks!

dkirk

First I would like to thank Michael S for discovering this wonderful solution, thank you sir! I just never liked the other bracket type solutions out there, looked too "after-market-ish" for me. I took your discovery and machined the ends off one side and made AL spacers per your description, turning them both down on a lathe and mill. The result of the lathe work is shown here. My pulley did not need the notch shown in Michael's photo, it just plugged in. I did have a good deal of trouble finding the 4.75" x .5" bolt needed for the top. I really wanted a flanged hex but the local bolt shop did not have one that long in stock so I opted for a plain hex (zinc) bolt at 4.5" which turned out to be not long enough. I just found that Mendards sells a 5" x .5" grade 5 zinc bolt so I'll grab one and shorten as needed. For whatever reason I didn't need to reverse the bolt like Michael needed, it JUST fits but I want a washer under the head if I can't have a flanged bolt. I did managed to get a serrated flanged nut on the back. A threaded rod with flange serrated nuts on both ends might be effective as well. If I take it off again I'll be tempted to paint it aluminum color to make it match better.

At 243,300 miles I waited WAY too long to make this modification and again, many thanks to Michael S for this wonderful discovery.











Wow, sorry for the dirty engine compartment!

wilcar

I used a dorman 34157 to delete my 84's ac compressor. Pretty much a bolt in. $41 on amazon.