How to: replacing the 4x4 front differential actuator

Well, since my 4wd drive stopped working, I decided to fix it my self.

Since my truck is a 92 and failed emissions, I decided to start with the vacuum hoses. Now I still had vacuum at the actuator i decided to replace them anyways since they were cracking and deteriorating and you can't inspect every inch of them without pulling them. That fix can be seen here:
http://www.automotiveforums.com/vbulletin/showthread.php?t=498411

Since that didn't work, onto the actuator.

Removal:

On my truck, you have to remove the battery and the battery tray to expose the culprit. On earlier models it might be bolted to the fender above the wheel well so you don't have to remove the battery.

http://img.photobucket.com/albums/v448/therealsundance/DSCF0187.jpg

You need to unbolt the frame from the wheel well. The two bolts are in the wheel well, no need to remove the tire.


Next, you need to disconnect the cable from the actuator. Use a screw drive to pry the spring from the slot and pull cable out.

http://img.photobucket.com/albums/v448/therealsundance/DSCF0191.jpg

Next, you can remove the cable from the frame by pushing in on the retaining tabs.

http://img.photobucket.com/albums/v448/therealsundance/DSCF0190.jpg

I skipped this step and just unscrewed the actuator from the housing and switched them out. I thought it would be easier than switching the frames out, too.



The problem:
http://img.photobucket.com/albums/v448/therealsundance/DSCF0193.jpg


The replacement part, $10 at the U pull it yard. Got it out of a 2nd gen truck. To make sure it was good when I pulled it, I just compressed it and put my finger over to inlet to see if it would hold the vacuum.

http://img.photobucket.com/albums/v448/therealsundance/DSCF0188.jpg

After removing the frame:

http://img.photobucket.com/albums/v448/therealsundance/DSCF0192.jpg


Now just bolt everything back up in reverse, and you are done.





BTW, this did engage my front differential! The only problem now is that the vacuum stays on all the time. :(

Tomorrow I replace the Vacuum switch in the transfer case. Part# 89059420

Another informative post.i sent it to the Faq suggestions thread.

Another great post laxman, thanks and keep up the great posts!!

Thanks guys.

There will be no how to on the vacuum switch. I couldn't get the new one to screw in. So I took it to my mechanic.

Sorry to hear about that laxman. Hope he doesn't get you for too much.

Thanks guys.

There will be no how to on the vacuum switch. I couldn't get the new one to screw in. So I took it to my mechanic.

I had a problem getting mine started too. But I had one of those little mechanics mirrors on a telescoping pole. I was able to get a good look at it with that and then starting it was easy.

Good how-to. Something I would like to add though. While doing this replacement. Check all your vac lines for cracks and dryrot and replaace as needed. Also check the vac lines and your old vac actuator for the presence of transmission fluid. If fluid is found the transfer case switch needs to be replaced as well. :)

Good how-to. Something I would like to add though. While doing this replacement. Check all your vac lines for cracks and dryrot and replaace as needed. Also check the vac lines and your old vac actuator for the presence of transmission fluid. If fluid is found the transfer case switch needs to be replaced as well. :)

He did.Lol he made an excellent how to on that.

Im gonna put a question i got in here since its basically the same.
Anyone know what year of the 2nd gen you can goto get this actuator thing?
I think i might pick one up and just replace it to see if this kicks the 4x4s ass since it goes in when it wants to. I got all new vac hoses and the switch so im gonna call it this actuator as the problem.

Im gonna put a question i got in here since its basically the same.
Anyone know what year of the 2nd gen you can goto get this actuator thing?
I think i might pick one up and just replace it to see if this kicks the 4x4s ass since it goes in when it wants to. I got all new vac hoses and the switch so im gonna call it this actuator as the problem.



Well, I pulled the replacement out of a 2nd gen for my first gen. I think it's the same up to the last year.

Yep. same from 83 to 04
http://www.1aauto.com/1A/4WDrive/ChevyTruck/S10Blazer/1AFWA00002/127514



For a little more money, you can get a jeep.
http://www.1aauto.com/1A/4WDrive/Jeep/Comanche/1AFWA00003/292587

Cool thats what i thought.Thanks

Just so you know this is what the cable operated alternative looks like

http://mypage.uniserve.ca/~kvsbt/scrap/4x41.JPG

the inside pull cable to engage the 4wd

http://mypage.uniserve.ca/~kvsbt/scrap/4x42.JPG

The cable it's self is verg good quality, but their supplied hardware is very cheap quality.

The advantage of this setup us you basicly have a low range 2wd, good for tight manuvers with a trailer on

I like that. I was seriously pondering slapping the posi lock system in it because of all the troubles with the system and that how it goes in automatically pretty much. But now that i know well i have known for awhile about this im gonna try to get one when i get to the jyd next.

It's a pretty basic system, if someone can find a source for the cable I'll rin to the hardware store and see if I can come up with a cheap alternative.

Other than the cable It's basicly only hardware store parts

I was concidering a posi-lock cable system too . But if it is cheap materials it is not worth the $100 plus dollars for it . I have searched for a rigid cable to use instead but I can't find one long enough to reach . Also check the vac lines and your old vac actuator for the presence of transmission fluid. If fluid is found the transfer case switch needs to be replaced Thanks for this tip rhilth , I have this problem too . I know what my next job will be . Rob

Look into heavy equiptment sales and parts. They use cables simular to the posi-lok's for the throttle.

To be perfectly honest I like the idea of the posi lok, and the quality of the cable, but I'm very disapointed in the quality it the rest of it.
If you look the cable housing is about an inch from it's clamp. Well it wasn't like that earlier, and the clamp was as tight as possible.
I got lucky that I didn't need 4wd that day, being in a snow storm in the back country. (it wouldn't have worked) This was the second time that the cable slipped in the cheap clamp.

The good thing though is it's always the same problem, and as long as I have the right Robertson screwdriver (yes that's right, they enclosed a robertson... square screw in the package) and a pair of pliers I can fix it in about 30 seconds.

I've actually taken the time to e-mail 4x4 Posi-Lok today, telling them that I can't recomend their product unless they've improved the quality, and tell me how to cure the problem that I have with mine (I really want them to send me a better quality cable clamp system)
I'm hoping that they respond with a solution, and I'll post any response (good or bad) from them here.

It is really the cheap quality clamps that I have the biggest issue with. If they change it to a quality, good design I would recomend their product.

http://www.eastcoastoffroad.com/posi/chevys.pdf

There is the link to a install sheet.

OBP didnt they give you the cool lock unlock cable dealy that is pictured in their. That i think is what threw me when you said you didn't have the right length cable.

They gave me the cable, and it should fit in either location.
The cheap hardware allowed the cable housing to slip, rendering it useless.

I might have worded it wrong.

Lol that makes sense to me now.

4x4 Posi Lok has not returned my e-mail, so that tells me that they DO NOT stand behind their products.

I know that I won't buy anything else from them.

Thanks for the heads up . I will look for other ways then . I have had several businesses that have not replyed to mine recently . Rob

Does this posi-lock cable system simply replace the need for the actuator? If its something like the switch on the x-fer case or the encoder motor that isn't working, will this setup still work?

It replaces the entire vacuum actuator

I'm getting rid of my auto hubs altogether soon, and it might be easy to talk my out of my posi lok.

Just so you know I'm still not happy with their customer service, or a better description is they don't have any customer service. I'll never buy another product from them.
My last post is over 4 months old and I still haven't heard back from them.

I don't think that you'll want to get rid of the auto hubs like I am. It's a lot of work and a lot of money, although it'll be tough. I've got most of the parts on a parts truck, so it's mostly fabrication for me.

I'd really like to get rid of that actuator system. I don't like it very much, especially with my problems with it lately, lol.

I liked the look of the cable system, too bad it has cheap hardware with it. I was interested when I first looked at it until you mentioned that part of it.

How hard do you think it would be to fabricate that type of system?

Not too hard at all, the cable it's self is the only hard thing to find. A throttle cable from an excavator or some other piece of equiptment would probably work.

I'm probably pulling it next week some time, if you remind me in about a week I'll take more pic's of it.

hi im trying to convert my 1989 chevy blazer from a 4x4 to a RWD if thats not to much trouble please help

my last post sayed

"hi im trying to convert my 1989 chevy blazer from a 4x4 to a RWD if thats not to much trouble please help"

and the reson for that is that i want to put air ride suspension in it but i want to no if its just cheaper to buy the 4x4 air ride suspension kit which is 3500 dollers and would converting it to RWD save me money if i do it myself becuz a regular air ride suspension kit would cost aroun 1500 thnks for reading. happy truckin lol

ok i just took off my actuator and it seems to work fine, when i plug the whole on the left side it holds pressure. But my question is was there supposed to be a vacuum line on the side of it?? And if so where is that vacuum line supposed to start? I've looked everywhere and can't find the damn thing.

my 89 blazer front wheels dont move but front driveshaft dose move