95 Blazer 4x4

[joehfd]

Originally Posted by NOVA71

I've had 3 of these trucks and 2 of them lost the 4wd because of a rotted vac line. Check the vac lines first. In both my cases it was the line that runs from the actuator under the battery behind the distributor (line #36 in the diagram posted by cailen). Both times it was cracked where it hooks in behind the distributor. Hope this helps.

Ok I've discoed tghe vacume line ai the accuater and checked for vacum coming out of the line when i engage 4wd, there is very little vacum at the line do you think its cracked or the check valve at the transfer case the culprit. the parts store told me they also go bad alot.
How strong should the vacum be?
joe

[Cailen]

Cracked, pinched, blocked. How is the fitting at the other end? You could try blowing it out with compressed air.

[joehfd]

Originally Posted by NOVA71

I've had 3 of these trucks and 2 of them lost the 4wd because of a rotted vac line. Check the vac lines first. In both my cases it was the line that runs from the actuator under the battery behind the distributor (line #36 in the diagram posted by cailen). Both times it was cracked where it hooks in behind the distributor. Hope this helps.

ok i dicoed the vacum line from the accuator and there is very little vacum coming from it, how strong should it be?
the parts guy told me it might be the check valve on the transfer case he sid they go bad all the time
joe

[Cailen]

Just to clarify, you mean the actuator by the battery yes? I don't have my Haynes and searching other posts hasn't yielded information on vacuum strength, so hopefully someone else can post that.

And I think your mechanic is talking about the vac switch on the Tcase. Yes, these are prone to failure, as they get sticky fairly easily. They are an inexpensive part (~$15)

[joehfd]

Originally Posted by joehfd

Ok thanks alot, i've narrowed it down to that i thought the actuator might have some corossion on it but it looks like that aint the case.

i'll try the vacume lines next, problem is you have to put everything back together to test it lol. anyway thanks for the info.
Joe
btw....NICE CAR

ok i tested the accuater and its seems to be working fine, when i engage 4wd its not pulling the cable all the way if i push it 1/4 of an inch or so i have 4wd could it be the accuator or something else
Joe

[NOVA71]

I just fixed the vac line on my 2000 last week. When I would push the 4hi button, I would hear the relay clicking and even the transfer case sounded like it was engaging the 4wd. The 4hi light would just keep flashing though and I'd have no 4wd. After a few weeks of randomly trying the 4hi I would still hear the relay but no sound from under the truck like it was engaging. When I checked the vac lines, the one that goes behind the distributor to the piece mounted on the firewall was off. One part of the line was still attached to the piece on the firewall. I figure it was cracked at first, that it why it sounded like it was trying to engage (prob just not enough vac to fully engage it). Than when the line totally split off, that it why I didn't hear it trying to engage anymore only the relay clicking. If yours is doing the same, I would definately check those vac lines. My last 2 blazers had that same vac line break in the same spot. And my first blazer had the sticking vac switch in the transfer case. It would usually stick in 4wd though. I used to have to pull the vac line off the actuator until I had the time to replace the vac switch. I would replace it usually every winter. Those are the only problems I've had with the 4wd on the 3 blazers I've owned.

[joehfd]

Originally Posted by NOVA71

I just fixed the vac line on my 2000 last week. When I would push the 4hi button, I would hear the relay clicking and even the transfer case sounded like it was engaging the 4wd. The 4hi light would just keep flashing though and I'd have no 4wd. After a few weeks of randomly trying the 4hi I would still hear the relay but no sound from under the truck like it was engaging. When I checked the vac lines, the one that goes behind the distributor to the piece mounted on the firewall was off. One part of the line was still attached to the piece on the firewall. I figure it was cracked at first, that it why it sounded like it was trying to engage (prob just not enough vac to fully engage it). Than when the line totally split off, that it why I didn't hear it trying to engage anymore only the relay clicking. If yours is doing the same, I would definately check those vac lines. My last 2 blazers had that same vac line break in the same spot. And my first blazer had the sticking vac switch in the transfer case. It would usually stick in 4wd though. I used to have to pull the vac line off the actuator until I had the time to replace the vac switch. I would replace it usually every winter. Those are the only problems I've had with the 4wd on the 3 blazers I've owned.

ok thanks but my line goes rite to the tranfer case there is vacume but don't no if its strong enough, honestly thats wut i think cause if if move the accuator 1/4 inch it works

[joehfd]

Originally Posted by joehfd

Ok thanks alot, i've narrowed it down to that i thought the actuator might have some corossion on it but it looks like that aint the case.

i'll try the vacume lines next, problem is you have to put everything back together to test it lol. anyway thanks for the info.
Joe
btw....NICE CAR

Ok just wanted to tell you guys that i was traceing vacume lines and came across 1 that was discoed by the master cylender on the firewall found out where it connected to and im back in buisness, ide like to thank you all for the help
Joe