few questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

berencam · 03-03-2008, 09:57 PM

k so question one is what is the easiest way to replace the freeze plug that is under the motor mount? question two, Somewhere allong the lines the tranny cooling lines where changed from metal to the rubber fuel type lines, that a problem or is it ok to use those? question 3, there is a little diaphragm on the transmission, kinda looks like the one on the distributor what is that for?

thanks for the help

Sinister · 03-03-2008, 10:03 PM

The "little diaphragm" on your tranny sounds like the vacuum modulator. I think thats what it's called. It has something to do with the tranny shifting. I would change out the cooling lines for metal if it was mine. Sorry can't help you on the freeze plug...

**Boog** · 03-03-2008, 10:11 PM

Hey Branson bud. Sinister is correct about the diaphram. It is a vacumn modulator and it senses engine load by vacumn to shift up. The cooling lines were probably bent up and crimped so someone just went the easy route and used rubber hose. They will work ok. May seep some fluid but will work. I also would find a good set of metal lines to replace them when I could. The freeze plugs behind the engine mount, now that's a little tougher. They are hammered in place so you'll need room to swing a hammer to knock the old ones out and put in new ones. The engine most likely has to be raised. Something to think about is if one of them is leaking the others are most likely in the same shape or near it. I would suggest the engine needs to come out to replace them all at the same time and be done with it. Maybe one of the guys has a better fix.

berencam · 03-03-2008, 10:17 PM

well i already replaced one and visually checked the others, what i was thinking was getting one of those freeze plugs with a a bolt in it with two washers and rubber in the middle, so you can tighten the bolt and nut and the two washers squeeze the rubber into the hole. well if i got one of those i thought mabee i could take the motor mount out and get one of those in the hole without taking out the engine?

berencam · 03-03-2008, 10:19 PM

and as for the vacuum modulator thingy? where that supposed to hook up to

**Boog** · 03-03-2008, 11:19 PM

There is supposed to be a hard line from the modulator up to the rear of the intake manifold. If your intake does not have a vacumn fitting already there there is most likely a plug in the hole. All types of fittings are available at your local parts store or salvage yard. Probably get the hard line and fitting off the same engine at the yard for cheap.

cdowns · 03-03-2008, 11:29 PM

checking freeze plugs visually is useless unless you have xray vision// they wear and corrode and fail from the inside out those rubber expansion plugs are sometimes good for 10 miles or so they like to blow out on the highway in the middle of nowhere not the easiest but the best way is pull the motor remove clean and replace them all
rubber tranny lines can be expected to fail at the worst possible time too
i've always had the tranny modulator hooked up off a vaccume tree rear center of the manifold same as where the power brake booster feeds from

03-03-2008, 09:57 PM	#1
berencam Registered User Join Date: Aug 2007 Location: branson mo Posts: 933	few questions k so question one is what is the easiest way to replace the freeze plug that is under the motor mount? question two, Somewhere allong the lines the tranny cooling lines where changed from metal to the rubber fuel type lines, that a problem or is it ok to use those? question 3, there is a little diaphragm on the transmission, kinda looks like the one on the distributor what is that for? thanks for the help __________________ 69 chevy c10 350 3 speed manual wood bed build thread here r.i.p. 70 c10 auto 350 build here

03-03-2008, 10:03 PM	#2
Sinister Between Trucks... Join Date: Mar 2002 Location: Los Angeles, CA. Posts: 3,830	Re: few questions The "little diaphragm" on your tranny sounds like the vacuum modulator. I think thats what it's called. It has something to do with the tranny shifting. I would change out the cooling lines for metal if it was mine. Sorry can't help you on the freeze plug... __________________ Beat it to fit, Paint it to match...

03-03-2008, 10:11 PM	#3
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 13,514	Re: few questions Hey Branson bud. Sinister is correct about the diaphram. It is a vacumn modulator and it senses engine load by vacumn to shift up. The cooling lines were probably bent up and crimped so someone just went the easy route and used rubber hose. They will work ok. May seep some fluid but will work. I also would find a good set of metal lines to replace them when I could. The freeze plugs behind the engine mount, now that's a little tougher. They are hammered in place so you'll need room to swing a hammer to knock the old ones out and put in new ones. The engine most likely has to be raised. Something to think about is if one of them is leaking the others are most likely in the same shape or near it. I would suggest the engine needs to come out to replace them all at the same time and be done with it. Maybe one of the guys has a better fix. __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross

03-03-2008, 10:17 PM	#4
berencam Registered User Join Date: Aug 2007 Location: branson mo Posts: 933	Re: few questions well i already replaced one and visually checked the others, what i was thinking was getting one of those freeze plugs with a a bolt in it with two washers and rubber in the middle, so you can tighten the bolt and nut and the two washers squeeze the rubber into the hole. well if i got one of those i thought mabee i could take the motor mount out and get one of those in the hole without taking out the engine? __________________ 69 chevy c10 350 3 speed manual wood bed build thread here r.i.p. 70 c10 auto 350 build here

03-03-2008, 10:19 PM	#5
berencam Registered User Join Date: Aug 2007 Location: branson mo Posts: 933	Re: few questions and as for the vacuum modulator thingy? where that supposed to hook up to __________________ 69 chevy c10 350 3 speed manual wood bed build thread here r.i.p. 70 c10 auto 350 build here

03-03-2008, 11:19 PM	#6
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 13,514	Re: few questions There is supposed to be a hard line from the modulator up to the rear of the intake manifold. If your intake does not have a vacumn fitting already there there is most likely a plug in the hole. All types of fittings are available at your local parts store or salvage yard. Probably get the hard line and fitting off the same engine at the yard for cheap. __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross

03-03-2008, 11:29 PM	#7
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: few questions checking freeze plugs visually is useless unless you have xray vision// they wear and corrode and fail from the inside out those rubber expansion plugs are sometimes good for 10 miles or so they like to blow out on the highway in the middle of nowhere not the easiest but the best way is pull the motor remove clean and replace them all rubber tranny lines can be expected to fail at the worst possible time too i've always had the tranny modulator hooked up off a vaccume tree rear center of the manifold same as where the power brake booster feeds from __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY



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