Hard hoses

[j_p_lockwood]

OK, so I replaced head gaskets, intake gaskets, etc on my 1995 3.1. I've done the job before, so I'm pretty confident in what I've done, but I have a fast idle and sometimes an uneven idle (fast-slow-fast). It's probably a vacuum leak (right?). The problem is that my hard hoses are really past their best... the one into the rear valve cover lost it's rubber fitting (temporarily sealed with gasket sealer to make it fit), and now the rubber end of the PCV valve hose broke. It's all so brittle. Is there any way to repair these things with stock parts, or should I just look for a replacement? If I still have a bad idle after sorting the hoses out, I'll have to get a pro to diagnose it, and hope he'll work for free.

Cheers

[kevinb70]

if you're going for vacuum leak ( ya can be unmetered air getting past causing the RPM fluctuation but not enough to throw a code)

assume the intake manifold is sealing well.

ya i know the connector you mentioned, has 3 rubber ribs that easily get worn down. I did same with mine and the RTV made a great seal. That same 1/2" hard hose goes right over the throttle body and there is a connector there that can get loose too. Put some RTV there too.

----

PCV - i bet you can find a 90-degree connector that will fit from general vacuum line parts or PCVs at autozone/advance. Mine is cracked as well, I just wrapped it with electrical tape and dabbed the inside with a light coat of RTV

----
hard hose running from manifold to the 'toilet float' (plastic ball shaped vacuum reservoir) attached to the plastic right in front of your tire.

Need to take out 3-4 screws and that plastic will drop down, bowl will be up inside there. I believe the engineers at chevrolet designed it, so that when the plastic flaps with the wind, it causes the toilet float to bounce up and down, eventually tearing the hard hose.

check the line as it goes past the battery, can get cracked there.

once you detach the hose from the vacuum reservoir, you can gently pull the line out, then use your mouth (or hand vacuum pump) at one end and finger over other end to check for leak.

Quick fix:

at autozone you can buy sleeves which can repair hard hose, just slip each end into the sleeve. For about $5 you can get hard hose of various sizes... i think it's 3 or 6 feet.

if the plastic hose is twisted and cracked at the reservoir, autozone sells a pack of several right-angle vacuum connectors. Once you look at the 90-degree connector that terminates the hard hose to the reservoir, you'll know you got the right replacements. There are a few of varying sizes, there are more than one that will fit. There is ample slack in the hard hose to make up for the 3/4" hose that broke off in the connector... don't bother trying to pull the hard hose out of the connector and reusing it... too much trouble and you might stretch it anyway.

If you want to prevent it twisting off again:
slide a few sleeves of heat shrink tubing on the hard hose before you install the 90-degree connector.... put the connector on, slide the heat shrink tubing onto the connector... hit it with some heat... heat shrink tubing will help reinforce the tube so that it flexes less.... or just use electrical tape and wrap it up.

----------

[j cAT]

Originally Posted by j_p_lockwood

OK, so I replaced head gaskets, intake gaskets, etc on my 1995 3.1. I've done the job before, so I'm pretty confident in what I've done, but I have a fast idle and sometimes an uneven idle (fast-slow-fast). It's probably a vacuum leak (right?). The problem is that my hard hoses are really past their best... the one into the rear valve cover lost it's rubber fitting (temporarily sealed with gasket sealer to make it fit), and now the rubber end of the PCV valve hose broke. It's all so brittle. Is there any way to repair these things with stock parts, or should I just look for a replacement? If I still have a bad idle after sorting the hoses out, I'll have to get a pro to diagnose it, and hope he'll work for free.

Cheers

with all the work you just did on this engine i'm surprised your asking this question. by new vacuum hoses there only 13years old common man. next if you need 90deg. vac fitting use copper tubing, this will outlast that engine. vacuum leaks cause engine wear as dirty air gets into the engine, get vacuum guage 21 inches at idle is good old brittle hoses must be replaced...............heat shrink is only temperary fix not made for this .............90deg vac fittings are hard to find, found plenty of t or cross fittings at auto parts store no L's.......if you think you have a leak or want to check intake manifold for vac leak use propane. attach a hose to end of propane torch direct the hose on area to test, if engine rpm increases you have leak. do not light torch. most auto mechanics use carb cleaner to do this then you'll need new hoses as the carb cleaner makes them brittle.........

[Blue Bowtie]

Another frequent place for vacuum leaks is the rubber bushing on the top of the throttle body, where the PCV source connects.