What brake booster is this? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Gigem · 02-13-2021, 08:53 PM

I have this leftover brake booster that I don't need anymore and want to sell.

I bought this for my 1972 GMC from LMC Truck. I have the old order, and the part number from LMC was 34-4321. See it here.

https://www.lmctruck.com/1967-72-che...-brake-booster

When it showed up at the guy's house who was helping me with the truck, he said that the booster didn't line up to the brackets on the truck. He said the bolt pattern on this booster was bigger than the bracket on the truck, if I recall. I ordered some new brackets from Jeg's, but instead of using them I found another booster somewhere else that fit the existing brackets so we ran with that.

Any idea what this booster is for? It was like $130 from LMC, and has never been used. I'd like to sell it and the Jeg's brackets, but I don't want to misrepresent the parts and mess someone else up.

Any thoughts? Thanks!

**MikeB** · 02-14-2021, 12:30 PM

Does your truck currently have the factory booster, or are you replacing a manual system?

BTW, several "thumbs-up" to you for being totally upfront about the booster. You're way too honest for eBay!

Just found this ~20 year-old photo of my 69 C10. The bracket, booster, master cylinder, and combination valve came out of a 71 or 72 junkyard truck. The booster leaked so I had it rebuilt in 1995, and it still works!

Andy4639 · 02-14-2021, 12:39 PM

With that bolt flange on the fire wall side of the booster I say it's a late model booster that mounted straight to the fire wall. As far as year I have no idea.

**MikeB** · 02-14-2021, 12:42 PM

That engine compartment looked so ugly back then, I just have to post this photo from 2 years ago!

**MikeB** · 02-14-2021, 12:45 PM

Quote:

Originally Posted by Andy4639

With that bolt flange on the fire wall side of the booster I say it's a late model booster that mounted straight to the fire wall.

Good catch. Also, what is the diameter? It should be around 11 inches.

Gigem · 02-14-2021, 06:05 PM

Quote:

Originally Posted by MikeB

Good catch. Also, what is the diameter? It should be around 11 inches.

Diameter is approximately 10.5 inches. The 4 bolts that hold it to the bracket are 3.5 inches on center.

There is a part number on the booster. 3M108. I google that and can't find anything.

I think I'll just put it on eBay with a lot of disclosure verbiage and these measurements and dimensions and see what happens.

68 TT · 02-15-2021, 05:21 PM

Quote:

Originally Posted by Andy4639

With that bolt flange on the fire wall side of the booster I say it's a late model booster that mounted straight to the fire wall. As far as year I have no idea.

I agree. With the size it may be the S10 Blazer or possibly Astro van version. The 88-up C/K trucks I have used a larger diameter and deeper profile version than that.

**Warrens69GMC** · 02-15-2021, 10:09 PM

MBM-11004

http://mbmbrakes.com/1967-1972-chevy...brake-booster/

Gigem · 02-16-2021, 12:19 AM

Quote:

Originally Posted by Warrens69GMC

MBM-11004

http://mbmbrakes.com/1967-1972-chevy...brake-booster/

Yeah, that! No idea why it didn't fit, but that is exactly what I have. Anyone need it???

**70STOVEBOLT** · 02-16-2021, 09:48 AM

That is a Delco Moraine style booster. A lot of our trucks used a Bendix style, but I think they will both work with the correct mounting brackets.

**MikeB** · 02-20-2021, 12:14 PM

Just occurred to me that LMC has a decent return policy. Have you called them?

https://www.lmctruck.com/faq/orders-...fore-returning

02-13-2021, 08:53 PM	#1
Gigem Registered User Join Date: Feb 2012 Location: Lakeway, TX Posts: 335	What brake booster is this? I have this leftover brake booster that I don't need anymore and want to sell. I bought this for my 1972 GMC from LMC Truck. I have the old order, and the part number from LMC was 34-4321. See it here. https://www.lmctruck.com/1967-72-che...-brake-booster When it showed up at the guy's house who was helping me with the truck, he said that the booster didn't line up to the brackets on the truck. He said the bolt pattern on this booster was bigger than the bracket on the truck, if I recall. I ordered some new brackets from Jeg's, but instead of using them I found another booster somewhere else that fit the existing brackets so we ran with that. Any idea what this booster is for? It was like $130 from LMC, and has never been used. I'd like to sell it and the Jeg's brackets, but I don't want to misrepresent the parts and mess someone else up. Any thoughts? Thanks! Attached Images __________________ 1972 GMC Sierra Grande (current truck) 1980 Chevy Stepside (gone) 1987 Chevy Blazer (gone) 1972 Chevelle SS Convertible (gone) 1973 Chevy Corvette (gone) 1967 Chevy Camaro (STOLEN!) Last edited by Gigem; 02-13-2021 at 09:13 PM.

02-14-2021, 12:30 PM	#2
MikeB Senior Member Join Date: Jul 2000 Location: North Texas Posts: 3,597	Re: What brake booster is this? Does your truck currently have the factory booster, or are you replacing a manual system? BTW, several "thumbs-up" to you for being totally upfront about the booster. You're way too honest for eBay! Just found this ~20 year-old photo of my 69 C10. The bracket, booster, master cylinder, and combination valve came out of a 71 or 72 junkyard truck. The booster leaked so I had it rebuilt in 1995, and it still works! Attached Images __________________ Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! Last edited by MikeB; 02-14-2021 at 12:37 PM.

02-14-2021, 12:39 PM	#3
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: What brake booster is this? With that bolt flange on the fire wall side of the booster I say it's a late model booster that mounted straight to the fire wall. As far as year I have no idea. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

02-14-2021, 12:42 PM	#4
MikeB Senior Member Join Date: Jul 2000 Location: North Texas Posts: 3,597	Re: What brake booster is this? That engine compartment looked so ugly back then, I just have to post this photo from 2 years ago! Attached Images __________________ Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then!

02-15-2021, 10:09 PM	#8
Warrens69GMC Registered User Join Date: Jan 2003 Location: Safford,AZ Posts: 3,622	Re: What brake booster is this? MBM-11004 http://mbmbrakes.com/1967-1972-chevy...brake-booster/ __________________ 1969 307, t350 1950 Chevy Wagon 1978 Big 10 1967 C10, 250,3-OTT

02-16-2021, 09:48 AM	#10
70STOVEBOLT Senior Member Join Date: Jun 2005 Location: Winona Lake, IN Posts: 6,414	Re: What brake booster is this? That is a Delco Moraine style booster. A lot of our trucks used a Bendix style, but I think they will both work with the correct mounting brackets. __________________ 70 C/10 SWB 402/TH400/3.73 "The Needy Beast" 200,000 Mile Club Disc Brake Club Owner installed options: Front Sway Bar Power Steering Power Brakes Cigar Lighter Courtesy Lights Deluxe Side Markers Wiper Delay Sliding Rear Window Power Windows Power Locks Sniper EFI 2015 Silverado 1500 LS 4.3/6L80/3.23 lowered 2" front & rear

02-20-2021, 12:14 PM	#11
MikeB Senior Member Join Date: Jul 2000 Location: North Texas Posts: 3,597	Re: What brake booster is this? Just occurred to me that LMC has a decent return policy. Have you called them? https://www.lmctruck.com/faq/orders-...fore-returning __________________ Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then!



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