1A Auto Video Library
Our how-to videos have helped repair over 100 million vehicles.
Enter Vehicle Year Make Model

Specify your vehicle's year, make and model to guarantee fit.

Year
Make
Model
Options
Drivetrain

How to Replace 4WD Front Axle Vacuum Actuator 1991-2004 GMC S-15 Sonoma

Created on: 2012-03-02

Learn how to replace the front axle vacuum actuator on your 94-04 GMC Sonoma or Chevy Blazer. 1A Auto will show you how to do it in this video.

  1. step 1 :Removing the Battery
    • Use an 8mm wrench to disconnect the negative battery cable
    • Use an 8mm wrench to disconnect the positive battery cable
    • Remove the 13mm battery mounting bolt
    • Remove the battery mount
    • Remove the 13mm bolts that connect the battery tray to the radiator support
    • Pull out the battery tray
  2. step 2 :Disconnecting the Vacuum Actuator Cable
    • Pull off the wire clip
    • Disconnect the cable
  3. step 3 :Removing the Vacuum Actuator
    • Remove the two 13mm bolts from the wheel well bracket
    • Remove the vacuum actuator cable from the bracket
    • Remove the 7mm bolts from the bracket
    • Separate the vacuum actuator from the bracket
  4. step 4 :Installing the New Vacuum Actuator
    • Attach the new actuator to the bracket
    • Tighten the 7mm bolts
    • Thread the 13mm bracket bolts through the wheel well and bracket
    • Tighten the 13mm bolt
    • Connect the cable to the actuator
    • Lock the cable into the cable bracket with a flat head screwdriver
  5. step 5 :Reattaching the Battery
    • If the battery tray clip has fallen into the engine bay, remove the headlight
    • Retrieve the battery tray clip with an extendable magnet
    • Put the headlight back into place
    • Put the tray clip into place
    • Put the battery tray into place, front first
    • Then slide the rear bolt hole over the bolt
    • Insert the two 13mm bolts into the radiator support
    • Putt the battery on the tray
    • Put the battery mount in place
    • Tighten the 13mm battery mounting bolt
    • Reconnect the positive battery cable
    • Reconnect the negative battery cable

Tools needed

  • 13mm Socket

    Socket Extensions

    Flat Blade Screwdriver

    8mm Wrench

    1/4 Inch Socket

    8mm Socket

    7mm Socket

    Telescope magnet

    Slip-Joint Pliers

    Ratchet

Brought to you by 1AAuto.com, your source for quality replacement parts and the best service on the Internet.

Hi. I'm Mike from 1A Auto. I hope this how-to video helps you out and next time you need parts for your vehicle, think of 1aauto.com. Thanks.

In this video we're going to replace the vacuum actuator for the front axle on this 2003 S15 Sonoma same as any S15 pickup as well as the Jimmy. Also the same as the S10 Blazer and pickup for the Chevrolet and these things sit under the battery so they can be exposed to some extreme conditions and sometimes the rubber diaphragm can dry out and crack and break and cause it not to operate.

Tools you'll need are an 8-mm wrench or socket and ratchet to disconnect the battery, 7-mm, 1/4-inch and 13-mm sockets. I use the ¼ inch because some of my bolts were a little bit rusty and then some pliers and a small flat blade screw driver.

Okay take an 8-mm wrench or socket and ratchet and disconnect your negative battery cable and your positive battery cable. Speed up here as I do that. I disconnect them and I pull the cables right over here. I'll use a 13-mm socket with a ratchet extension and remove this bolt and this clamp. Speed up again as I remove that battery mounting bolt and the mount itself. Okay, so once those are removed, take the battery right out. Okay you want to remove your battery tray. You want to remove two bolts into the radiator support one there and then one right here. Those are 13-mm. Speed up again as I remove those two bolts. Okay now pull the back of the tray up and off that bolt and right out.

Now right in here is your top of your cable. You should be able to take this, squeeze it and that should move pretty easily. Okay sometimes these cables will get frozen up and they won't move if you don't use them very often. To unhook the cable all you want to do is pull up on this little clip. It's like a wire clip. Pull it up and out. Okay, and then you can see that the cable can come right out.

Okay, here in your passenger's wheel well, I've turned the well all the way to the left. There are two bolts that hold that bracket. I'm going to remove those. Fast forward here as we remove those two 13-mm bolts. Now I can bring this right up and use a pair of pliers and squeeze these teeth right here. Force the cable through. And now you want to use a . these bolts are 7mm but they were pretty rusty and crusty on this vehicle so I used 7mm and I'm able to get that middle one out, but then I shift down to a ¼ inch socket and you'll see that later to try and get it on to the other two bolts. You can see I put it on there and it basically just kind of slips off of it because the head of the bolt is so rusted. Okay so 7mm didn't work so I went down to ¼ inch standard size. I'll see if I can hem this on there.
Okay here's the new part from 1A Auto. As I said there's nothing wrong with my old one so I'm going to reinstall my old one on this vehicle, but the new one is just like the original. It's going to mount into the bracket correctly. Okay, it has the wire clip and everything. All you do is insert the cable in there and make sure it locks in well.

Speed it up here again as a reassemble the old actuator on there and again tighten these bolts up. You want to make them snug but not too tight. And now grab your bolts and make sure you reconnect the vacuum line and reach back under and mount in the 13-mm bolts that hold that bracket.

Here I'm fast forwarding through. I'm holding the actuator and bracket in my other hand that you can't see and then just threading the bolt in from the wheel well side and then tightening them up nice and snug. Again, they don't have to be extremely tight. Make sure we have our clip in place for this actuator here and put the cable through and in there. Make sure the cable goes in there and actually push it in so that they're moving as one. Okay. Push the cable into the bracket here and use a small screw driver to pry up those ears and make sure it's locked in place.

Okay, before you go and put your battery tray in, what happens a lot is the clip get knocked off up here or your clip up on your headlight. Okay pull your headlight out and usually that clip falls right down in here. And here I'm using a little extendable magnet to fish the clip out. Put our lights back in place. This clip goes right back on here like that. Okay now I'm going to put the battery tray in. You want to put the front down in first and then the back down over the bolt. Put the two bolts into the radiator support and then you'll put the battery back down in, put the mount in and then the nut and you should be all finished. Then reconnect your battery. You want to connect the positive cable first and then the negative cable and you should be all set to go.

We hope this helps you out. Brought to you by www.1AAuto.com, your source for quality replacement parts and the best service on the Internet. Please feel free to call us toll-free, 888-844-3393. We're the company that's here for you on the Internet and in person.


Share on:
Copy URL
Go To Top
Same Day Shipping

Need your part faster? Choose expedited shipping at checkout.

Guaranteed To Fit

Highest quality, direct fit replacement auto parts enforced to the strictest product standards.

USA Customer Support

Exceeding customers' expectations, our team of passionate auto enthusiasts are here to help.

Instructional Video Library

Thousands of how-to auto repair videos to guide you step-by-step through your repair.