Author Topic: How to remove these bolts for heater core access  (Read 4832 times)

Offline LiamC20Chev

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How to remove these bolts for heater core access
« on: November 26, 2017, 03:41:32 AM »
Does anyone know how to remove the bolts or where to access them from.
My heater core was leaking (as you can see by some of the rust that’s started to form) so I want to replace it. Have gotten this far but no idea where to get access to these bolts, the round headed ones.

Any help would be greatly appreciated. Thanks in advance!




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Offline impco lpg

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Re: How to remove these bolts for heater core access
« Reply #1 on: November 26, 2017, 05:16:50 AM »
there are nuts on the other side of the fire wall that need removing first
1983 cucv m1009  blazer 6.2 4x4
1991 1500 suburban 5.7 4x4 lpg
2003 dodge ram 5.7 4x4 lpg
1985 chevy c10 stepside  2wd 5.7ltr 350 lpg

Offline Henry

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Re: How to remove these bolts for heater core access
« Reply #2 on: November 26, 2017, 10:14:05 AM »
Hi:
Yeah the nuts on those captive studs are on the engine side of the firewall. I recall them being fine thread with an integral large diameter washer. I recall the lower one being very difficult to get to as it is low down and in a tight area between the fender skirt and firewall and under the A/C fiberglass shroud. If you dont have the A/C shroud maybe it wont be so bad. You need to inspect the threads before loosening the nuts because they are notorious for becoming very rusty over time and you can easily strip the nut on the stud or spin the stud and then you have a real problem. If they are real rusty just get some lube on them before loosening. They are not supposed to be real tight and I recall there being a rubber washer under the nuts as well. They also may be all covered with undercoating that you would have to chip away. Even after you get them off, you need to gently wiggle the heater housing out of the firewall-those stud threads are going to hang up on the firewall and if you get too rough with the removal you can flatten the threads easily on the firewall sheet metal holes and then you need some new studs which are not readily available...I think I found some at Eckler's Camaro parts a long time ago. Big job, be patient.
Good luck,
Henry

Offline ehjorten

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Re: How to remove these bolts for heater core access
« Reply #3 on: November 27, 2017, 08:40:48 AM »
I find it much easier to remove the nuts holding it to the firewall after removing the inner wheelwell!  There is one bolt on the far RH side of the heater box that goes in from the inside of the cab.  The rest are studs with nuts on the engine side of the firewall.  A good idea is to chase the extra length of the stud with a thread chaser or tap before you remove the nuts.  As others have said...the nuts could be a real bear to remove depending on the condition of the ends of those studs.  I don't recall what size the bolts are, but possibly 1/4"-20.  You can break your plastic heater box or ruin the retainer on the end of the studs if you crank on them too hard trying to get the nut off.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline blazer74

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Re: How to remove these bolts for heater core access
« Reply #4 on: November 27, 2017, 01:17:46 PM »
Do your self a favor and pull the inner fender loose as suggested to access those nuts  to prevent damaging the housing.
Depends on condition of the bolts for the inner fender also  as far as removing or how hard to.

WD40 or such goes a long way.
The battery also sits on the rt inner fender on some.

Offline ehjorten

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Re: How to remove these bolts for heater core access
« Reply #5 on: November 27, 2017, 01:35:06 PM »
I have always been able to remove the inner fender without even removing the wheel.  It does require you to jack the frame up and let the wheel droop down some, but the inner fender will then come out without much effort at all!  As stated by Blazer...the bolts to remove the inner fender and the speed-nuts may or may not put up a fight.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline LiamC20Chev

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Re: How to remove these bolts for heater core access
« Reply #6 on: December 01, 2017, 07:34:14 PM »
Thanks for the replies guys. Sounds like removing the inner wheel arch is the go. I’ll set aside a day and take my time with it.
Funny when I bought the truck the original owner told me the heater just started leaking and that I’d need to just “swap it out”...made it sound so simple, not to mention the rust I discovered. Seems it was leaking for quite some time.

Thanks again guys


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Offline Henry

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Re: How to remove these bolts for heater core access
« Reply #7 on: December 03, 2017, 11:13:40 AM »
Hi Liam:
Yeah it is actually a pretty big job for a shade tree mechanic at home, but once you know what the plan is you can move through it without breaking too many other parts. When I took mine apart the gaskets in the heater housing all crumbled and fell apart so I bought some sheet closed cell foam from McMaster-Carr and cut out new ones and glued them on with spray adhesive. I kept paper templates for the gaskets for the next time! While you are in there it is a good time to inspect some of the other rubber hoses that you normally cant get to and the firewall for water leak points.
Regards,
Henry