47-55.1 Aftermarket Brake Booster Question

[Dachshund]

Working on a 1947 3600.....
I have a disc brake kit lined up, but every MC/booster I see are for auto transmission only. Is this due to clearance issues? I'd like to keep the MC where it is, and am staying with the manual trans. Anyone know where to get a MC/Booster (or just the bracket) that works with the manual trans?
I have been wondering about just using the M/C without the booster.....any ideas?

[mr48chev]

I'd have to say that most people going to an aftermarket booster are also installing an automatic and the market for boosters for trucks with manual trans is considered too small to address by the manufacture. They can sell 100 of the ones for automatics a month but get an inquire for one with a clutch pedal every two or three months.

Guys do it though as they usually buy just the booster and master cylinder and fab a bracket that mounts it further back on the frame rail and build a stout and longer pushrod to actuate it. For the ugly look of booster in the engine compartment guys usually use donor pedals that work snagged from another vehicle.

[dsraven]

it's all got to do with the clutch pedal pivot linkage being in the way. like mr48 says, just mount the booster further back. another thing you might consider is a hydroboost set up. it is smaller, so less bulk under the cab,and also may have a better brake boost effect. they run off the power steering system so it would be hydraulic hoses or steel lines with short flex hoses on the ends.

ebay pic, doesn't show frame bracket

https://www.ebay.com/itm/1947-1955-C...4AAOSws5BaVm4C

generic frame bracket pic, ebay, simple to build if so inclined

https://www.ebay.com/itm/1947-55-Che...k%7CMake%3AGMC

another with disc brake master attached. sub the hydroboost in between the bracket and the master cyl.
https://www.ebay.com/itm/1947-55-Che...k%7CMake%3AGMC

ogre's set up on a 55-59.

http://67-72chevytrucks.com/vboard/s...=484368&page=2

kim57's mounted further back on the frame using the ebay style brackets. check post 200 for pics

http://67-72chevytrucks.com/vboard/s...t=kim57&page=8

another whole thread on the hydroboost subject

http://67-72chevytrucks.com/vboard/s....php?p=7531548

that should keep you busy, haha

[dsraven]

you could also run a hydraulic clutch set up to save space under the cab

[dsraven]

https://www.classicindustries.com/product/am530099.html

or cable operated somehow. gotta be one out there.

[nvrdone]

ive got a kit that the mfg says is for an auto trans. but guess what -- it works great with my m21 4 spd. I don't see where the problem is. the booster and m/c mount in line with the brake pedal on the back side of the linkage. the clutch pedal clears it with lots of room on mine. I can look up the invoice from when I bought it & get you that info if you're interested

[1project2many]

another thing you might consider is a hydroboost set up. it is smaller, so less bulk under the cab,and also may have a better brake boost effect.

I would recommend using a Ford ydroboost unit. The GM units have a wider mounting flange than their vacuum boosters and it's tough to find a master cylinder smaller than 1.25" that fits.

[Dachshund]

Originally Posted by nvrdone

ive got a kit that the mfg says is for an auto trans. but guess what -- it works great with my m21 4 spd. I don't see where the problem is. the booster and m/c mount in line with the brake pedal on the back side of the linkage. the clutch pedal clears it with lots of room on mine. I can look up the invoice from when I bought it & get you that info if you're interested

Thanks! I would be interested in finding out who you bought it from, and which one you bought~

[Dachshund]

Thanks for the replies, Guys!

[dsraven]

when you get it figured you you can thank us with a few pics of what you are up to. we all love pics, i gets us fired upon our own stuff.

[nvrdone]

the brake booster mount was from No Limit Engineering in San Bernardino CA.

p/n pbc47 at a cost of $107.00. but that was way back in 2002. this is just the bracket & fittings. The m/c & booster I got from NAPA. Booster is 77163, m/c is 10-1602

[Dachshund]

I'm still confused as to why one of those "kits" wont fit. Isn't the mount BEHIND the transmission mount? On my truck at least, there is nothing in the way - unless I'm missing something!

[dsraven]

would this video help? yours is different than this?
pics would help

http://blog.brotherstrucks.com/1947-...-installation/

[dsraven]

it's been awhile since I worked on my buddy's '54 but I seem to remember a pedal pivot pin actually cast into the master cylinder, not a stud attached to the frame ahead of the master cylinder like the brothers video shows. how is your set up configured?
again, a pic would tell a thousand words....

[dsraven]

these guys sell lots of brackets and hotrod fabrication stuff. maybe they have something you could make work. they are Canadian so the USD goes further. they also have a tech line if you need to ask a question.

https://www.welderseries.com/Brake-Pedal-Kits-c13194938

[dsraven]

check post 4, maybe private message the owner of the yellow unit and ask some questions and maybe get some answers as to how he made it work.

http://67-72chevytrucks.com/vboard/s...d.php?t=779701

[dsraven]

I know, wrong year, but sorta same set up.

[Dachshund]

Originally Posted by dsraven

it's been awhile since I worked on my buddy's '54 but I seem to remember a pedal pivot pin actually cast into the master cylinder, not a stud attached to the frame ahead of the master cylinder like the brothers video shows. how is your set up configured?
again, a pic would tell a thousand words....

Well, I have everything removed, but it is like the video - the M/C mounts behind the bracket for the pedals. I only have a front bracket under the transmission, though, no rear cross member...

[dsraven]

stock engine mounts from the front and then attaches to the bell housing which sits on 2 rubber puck mounts that basically rest on the cross member behind the engine and the trans hangs behind that with a torque tube driveline to the rear axle, correct? not sure what the clutch linkage looks like but by the pedal arrangement it has to pivot on the same shaft as the brake pedal.
again, some pics would help.

[Dachshund]

Originally Posted by dsraven

stock engine mounts from the front and then attaches to the bell housing which sits on 2 rubber puck mounts that basically rest on the cross member behind the engine and the trans hangs behind that with a torque tube driveline to the rear axle, correct? not sure what the clutch linkage looks like but by the pedal arrangement it has to pivot on the same shaft as the brake pedal.
again, some pics would help.

You are correct! It is just like in the Brother's video. I hope to get a kit similar to the one shown in their video, but am wondering WHY it's for auto trans only.....I don't have photos because it is all been removed for sandblasting the frame - and my computer died, so I am on a borrowed machine or my phone. I'm just wondering if there is another reason it won't work with the OEM 4-speed. It CAN'T be because it will hit some thing - it doesn't look like there is anything TO hit!

[nvrdone]

when I did my pb conversion the only problem was that the m/c wouldn't clear the stock trans mount - the one at the end of the tail shaft. so I just made a new one out of tube that mounts under the frame & clears the m/c. easy done.

[Dachshund]

Originally Posted by nvrdone

when I did my pb conversion the only problem was that the m/c wouldn't clear the stock trans mount - the one at the end of the tail shaft. so I just made a new one out of tube that mounts under the frame & clears the m/c. easy done.

Mine does not have a rear trans mount......

[dsraven]

is it possibly because this bracket would need to be removed to install the p/b bracket so then you wouldn't have a pivot and linkage for your clutch pedal? I dunno. been too long

https://www.ebay.com/itm/47-48-49-50...-/123017242353

[Dachshund]

From what Brother's told me, they say that the stock clutch linkage interferes with the way the brake pedal hooks up to the new booster....OUGHT to be a way around that...

[dsraven]

yep, that's why they call it hot rodding, because a lot of what is done isn't word for word out of the instruction manual put together by someone who has never seen the end result. mostly it's because there is no off the shelf part made for the purpose. it is also because the price tag for those parts, if available, prohibits the purchase so guys just build what they need from parts off other vehicles they already have or can get cheap.
if I were you I would fab something up that works. cheaper, probably gonna be stronger and you get what you need. personally I would use a hydroboost just for it's smaller size and no need for a vac line to run way down there. that's just me though. there would be hydraulic lines but they could be steel for the most pat, with flexible parts on each end
leave the pedals and clutch linkage where they are, connected (clutch) with the brake pedal held at the top of it's stroke. get rid of the master cylinder and clean up the area of rust, dirt, grease etc. then get a booster and master that is gonna work for your brake system, then fab some brackets that will hold everything where you need it and still work for the clutch linkage. ensure the clutch linkage can do a full stroke plus some extra room for working on it. maybe use a booster mounting bracket you can purchase separately or buy the whole booster/master/prop valve assembly built for the automatic trans version of your truck and simply modify it to be further down the frame? I think I seen one set up where the builder simply used the original master cylinder, gutted and drilled through, as a guide for the pushrod to run through and then mounted the aftermarket booster/master behind that down the frame a way. it may not be spaced far enough out from the frame though, not sure.
anyway, where there is a will there is a way, you can figure it out.
what my dear old granny used to tell me.