Carburetor bottom base to middle section bolts

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bbolander
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Carburetor bottom base to middle section bolts

Post by bbolander » Thu Apr 13, 2017 9:07 pm

Our carb rebuild came to a halt tonight. We couldn't get two of the bolts that attach the base to the middle sections out. The two we did get out were extremely difficult to remove. They look like they were heavily loctited. We're soaking the remaining two in PB Blaster tonight.

Any hints on getting these out and why it's so hard?
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IMG_1732 copy.jpg (439.42 KiB) Viewed 636 times
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IMG_1733 copy.jpg (412.81 KiB) Viewed 636 times
1971 Pinzgauer 710M, all stock including 245-16 Maloya tires, taken off and stored for show
BFG MT KM2 265/75R16's on Black SAV replacement rims on now

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Jimm391730
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Re: Carburetor bottom base to middle section bolts

Post by Jimm391730 » Thu Apr 13, 2017 9:36 pm

Dry them thoroughly (no fumes) then put them in a 250F oven for an hour. When good and hot, take them out and immediately try to remove the screws with a proper fitting screwdriver. They should come loose. If not then continue to try the PB Blaster.
Jim M.
712W and 710M

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bbolander
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Re: Carburetor bottom base to middle section bolts

Post by bbolander » Thu Apr 13, 2017 9:49 pm

Thanks. When we put them back in, should we use loctite? Blue?
1971 Pinzgauer 710M, all stock including 245-16 Maloya tires, taken off and stored for show
BFG MT KM2 265/75R16's on Black SAV replacement rims on now

63rover
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Re: Carburetor bottom base to middle section bolts

Post by 63rover » Fri Apr 14, 2017 8:37 am

I doubt the white mess on the screws is loctite. It looks like aluminum oxide created by electrolytic action between the screws' steel and the carb body's aluminum. They are stuck because rust (not iron oxide in this case but aluminum oxide) is a form of welding. It's likely those screws have never been removed since the carb was manufactured.

The heat idea is a great one. If it doesn't work at 250 try increasing it to 350 an then 450. The casting should handle the temperature with no issues.

Good luck!

Cheers, Clive

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bbolander
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Re: Carburetor bottom base to middle section bolts

Post by bbolander » Fri Apr 14, 2017 12:42 pm

Thanks to both of you. This morning the PB Blaster was still sitting in a puddle on top of the bolt heads, so I doubt if it penetrated much.

Heating in the oven at 250F for an hour worked to separate the base from the upper section. But the bolts still didn't want to come out of the base section. So I heated up the base at 250F for an hour and tapped the bolts out using a punch on the end and they came out fine.

The two bolts in the picture are replacements. The two that were hard to get out are black and only threaded on the upper section end.

Great responses on this forum!
1971 Pinzgauer 710M, all stock including 245-16 Maloya tires, taken off and stored for show
BFG MT KM2 265/75R16's on Black SAV replacement rims on now

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Jimm391730
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Re: Carburetor bottom base to middle section bolts

Post by Jimm391730 » Fri Apr 14, 2017 1:00 pm

The reason I suggested 250F is this temperature is not likely to do much, if any, damage to anything not metallic - plastic, O-rings, etc. You can always go hotter but often 250F is effective.

Our 710M was always loosing the top screws until we started using blue Locktite on them; others have had the lower bolts loosen until they did the same.
Jim M.
712W and 710M

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bbolander
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Re: Carburetor bottom base to middle section bolts

Post by bbolander » Sat Apr 15, 2017 9:42 pm

We did the same 250F for 1 hour on the front carb base bolts, worked well on it too. Great input!
1971 Pinzgauer 710M, all stock including 245-16 Maloya tires, taken off and stored for show
BFG MT KM2 265/75R16's on Black SAV replacement rims on now

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Hotzenplotz
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Re: Carburetor bottom base to middle section bolts

Post by Hotzenplotz » Wed Apr 19, 2017 5:19 am

I swapped these screws for DIN 7984 low head inbus screws M6 x 40 mm.
Image
Makes life much easier next time ...
Cheers
Albert
========================
My Pinz has NEVER been with any army

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bbolander
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Re: Carburetor bottom base to middle section bolts

Post by bbolander » Wed May 03, 2017 10:53 pm

We used Loctite Blue when re-installing the bottom bolts about 3 weeks ago. We had to separate the bottom again yesterday to install new accelerator pump valves, and the bolts cracked open pretty easily with the Loctite Blue. So I think the original problem was corrosion.

BTW, I had ordered new bottom bolts and lock washers from SAV since the screwdriver slots on ours were starting to wear a little. I received 8 shoulder bolts, but each carb only uses 2 shoulder bolts for positioning. The shoulder bolts won't go into the other two holes. The washers that SAV sent were too small for the shoulder bolts so I had to re-use the old ones. The washers SAV sent fit fine on the non-shoulder bolts that I had to re-use. A heads up when ordering new bottom bolts and washers.
1971 Pinzgauer 710M, all stock including 245-16 Maloya tires, taken off and stored for show
BFG MT KM2 265/75R16's on Black SAV replacement rims on now

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