Brake Booster for a '66 Wagoneer

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AZOutdoors
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Brake Booster for a '66 Wagoneer

Post by AZOutdoors »

The last part I need to replace on my '66 Wagoneer's brakes is the power booster. I have not been able to find a booster that says it will fit. BJ's has one that says it will fit a '67-'72 that looks like it, but the tech said it will not fit. He suggested going to a Hydra-Boost system which I may consider doing someday but for now would prefer a booster swap. I do not see any markings on it other than a remanufacture tag (I have not removed it yet to see if there are markings I can't see). Any ideas from anyone?
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Harry Dawg
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Re: Brake Booster for a '66 Wagoneer

Post by Harry Dawg »

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tgreese
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Re: Brake Booster for a '66 Wagoneer

Post by tgreese »

Suggest you send it to a booster rebuilding service. Likely replacements are not available because there are no cores. (Or the cataloging and inventory costs exceed any profit to be made. Nearly half a century old, and an oddball.).

Example: https://brakeboosterrebuild.com/about/ - not a rec, this is the first that came up.

https://www.bing.com/search?q=brake+booster+rebuilder

Or you can buy a hot rod booster and adapt it. Check Summit Racing or Jeggs.

Hydroboost is another option, if you have power steering. Can be done with junkyard parts - https://www.modsandrods.tv/2019/12/27/h ... a-hot-rod/
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
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Harry Dawg
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Re: Brake Booster for a '66 Wagoneer

Post by Harry Dawg »

Currently debating adding a brake booster to my 68' J3000
I understand disk brakes require a greater amount of pressure to operate compared to drum brakes, so after converting the front to disks I think I may need to upgrade the MS/Booster.
I haven't test drove this rig yet so I can't confirm. They might work fine.
Currently it is a dual reservoir with no booster
@Tgreese - You seem to have sounds conceptual knowledge of automotive systems.
Is there a formula for determining how much line pressure a current setup can produce? Maybe something like Bore x Stroke = ?
How do you determine the multiplying factor of a brake booster?
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devildog80
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Re: Brake Booster for a '66 Wagoneer

Post by devildog80 »

Reason to replace the booster!

Is it not working correctly?

Maybe just a vacuum leak?

Perhaps just a bad fitting or gasket?

Trouble shoot and let us know :)
AZOutdoors wrote: Wed Aug 03, 2022 8:10 am The last part I need to replace on my '66 Wagoneer's brakes is the power booster. I have not been able to find a booster that says it will fit. BJ's has one that says it will fit a '67-'72 that looks like it, but the tech said it will not fit. He suggested going to a Hydra-Boost system which I may consider doing someday but for now would prefer a booster swap. I do not see any markings on it other than a remanufacture tag (I have not removed it yet to see if there are markings I can't see). Any ideas from anyone?
'81 CJ5 Base, 258 I6, MC2100, T176 4 spd, 300 TC, D30 Front NT, 3.31, 2-Piece AMC 20 rear NT, 3.31, 4" high arc spring lift
'84 Grand Wagoneer, 401 V8 (.030 over), MC2150 HA Comp, 727 auto, Selec-trac NP229, AMC 20 REAR - D44 FRONT - WT 3.31, 4" high arc spring lift
Rather be driving, than waiting to be modified
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tgreese
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Re: Brake Booster for a '66 Wagoneer

Post by tgreese »

Harry Dawg wrote: Wed Aug 03, 2022 8:45 am ...
@Tgreese - You seem to have sounds conceptual knowledge of automotive systems.
Is there a formula for determining how much line pressure a current setup can produce? Maybe something like Bore x Stroke = ?
How do you determine the multiplying factor of a brake booster?
Finding the force on the pads or linings is basic physics. Piston area times force in pounds equals pressure. The change in force between two cylinders is the change in diameter squared. The line pressures are hundreds of psi; quite a lot. A vacuum booster works by evacuating one side of a rubber diaphragm, and applying atmospheric pressure to the other. The push rod opens a valve that admits more or less air to move the diaphragm. Typically there is only a very small gap (20 thou? 30 thou? Something like that) between the input rod and the output rod, that moves the air valve.

I guess all this could be done from first principles if you know all the dimensions, but it's too much for me to do on a lark. I'd probably look at some existing brake systems and try to mimic the proportions of the components. The automotive engineers that designed these system undoubtedly spent a lot of time in this type of exploration. You might find something in the literature;, maybe even textbooks for said engineers that go into this.

(edit) If you know the booster diameter, you can get an idea of the maximum force the booster can exert in pounds. A 7" booster is 38 sq in of area; scale up or down for the diameter of the booster. I presume a double diaphragm booster doubles that. Engine vacuum is something like 15 inches of Hg (mercury) or about a 7 psi difference from atmospheric. 7 times 38 is about 270 pounds of force. Realize that the air valve meters the pressure difference on the diaphragm(s), allowing the driver to stop smoothly.
Last edited by tgreese on Wed Aug 03, 2022 3:01 pm, edited 1 time in total.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
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will e
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Re: Brake Booster for a '66 Wagoneer

Post by will e »

The reman tag shows up as a valid product (but out of stock) on Amazon:

https://www.amazon.com/Prior-2506532-Re ... B000C6B376

According to amazon this doesn't fit your truck (not surprising). A cross reference showed it fits in an 05 honda oddyssy. So perhaps someone modified an oddyssy BB to work? You might order one from the local parts store to see if it is the same, if not, just return it.
81 Waggy 'WILL E' Retired
82 Cherokee WT - SOA/SF/high steer/Alcan springs/agr box/Borgeson steering shaft/AMC 401/performer/holley TA/HEI/BeCool/727/ALTAS (2.0/2.72/5.44)/D60 Snofighter(Yukon Zip,hubs,stubs,4.56)/14 Bolt (FF,BF shave, Discs, ARB,Artec Truss)/MTR 37X12.5/Corbeau XRS Baja & 5 point retractable harness/Hella Aux lights/tuffy console/killer32 sliders/Evil Twin bumpers, rack and roll cage/WARN 8000/TT Fabworks steering brace/dual batts/custom TC skid plate/ARB fridge
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tgreese
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Re: Brake Booster for a '66 Wagoneer

Post by tgreese »

devildog80 wrote: Wed Aug 03, 2022 9:08 am Reason to replace the booster!

Is it not working correctly?

Maybe just a vacuum leak?

Perhaps just a bad fitting or gasket?

Trouble shoot and let us know :)
If it's not boosting, and the check valve and manifold connection ar ok, you pretty much have to condemn the booster. As mentioned, They have a big rubber diaphragm inside that boosts the pedal pressure with air. I expect it's like anything rubber - it cracks and fails with age. Reman of a booster is simple, except that there are oddball boosters that need oddball parts and treatment. This looks like a conventional design booster, but specific to these Wagoneers. Should be a snap for a specialty rebuilder (but not free).
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
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tgreese
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Re: Brake Booster for a '66 Wagoneer

Post by tgreese »

will e wrote: Wed Aug 03, 2022 9:13 am The reman tag shows up as a valid product (but out of stock) on Amazon:

https://www.amazon.com/Prior-2506532-Re ... B000C6B376

According to amazon this doesn't fit your truck (not surprising). A cross reference showed it fits in an 05 honda oddyssy. So perhaps someone modified an oddyssy BB to work? You might order one from the local parts store to see if it is the same, if not, just return it.
Good work to find that, but where do you get Honda? Seems very unlikely that Honda would use a Bendix part on their cars, esp. as late as 2005.

Again, no cores. Easy for a rebuilder.

(more) I would comment, that brake setup looks VERY Jeep to me. Hardly a swap. The cast plate on the dash should be a 939936. Look at the parts catalog, group 8 plate 12. Exactly what the OP has here. In the day, you could have bought a rebuild kit for this booster at the Jeep parts counter. 8.405-1, either 943451 or 948040, less/with tee or valve, resp.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

will e
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Re: Brake Booster for a '66 Wagoneer

Post by will e »

Found this picture, it's a 66 and it does look like it has the same bracket

https://barnfinds.com/luxury-suv-ancest ... agoneer-5/
81 Waggy 'WILL E' Retired
82 Cherokee WT - SOA/SF/high steer/Alcan springs/agr box/Borgeson steering shaft/AMC 401/performer/holley TA/HEI/BeCool/727/ALTAS (2.0/2.72/5.44)/D60 Snofighter(Yukon Zip,hubs,stubs,4.56)/14 Bolt (FF,BF shave, Discs, ARB,Artec Truss)/MTR 37X12.5/Corbeau XRS Baja & 5 point retractable harness/Hella Aux lights/tuffy console/killer32 sliders/Evil Twin bumpers, rack and roll cage/WARN 8000/TT Fabworks steering brace/dual batts/custom TC skid plate/ARB fridge

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AZOutdoors
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Re: Brake Booster for a '66 Wagoneer

Post by AZOutdoors »

Great sleuthing will e! I searched that reman tag number on Google and that Amazon link you found did not come up. Funny thing about that is Amazon is usually the first link that comes up on ANYTHING you search. Devildog80..the booster provides help but it looses effectiveness toward the bottom of pedal travel. Also, If I hold the pedal down and shut off the engine, the pedal starts to move up immediately instead of staying put for 30 seconds or so. I replaced the hose and check valve and the seal on the pushrod looked ok. As tgreese said, probably a failed rubber diaphragm. Checking now with some rebuilders (thanks again for that suggestion tgreese) and I may take it to a few parts places to see what they may have to try to match it.

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Re: Brake Booster for a '66 Wagoneer

Post by will e »

If you have a hand vacuum pump you can test if the diaphragm is holding vacuum. Even a new one won't hold vacuum 'forever' but they will hold it for at least a few minutes.

It wouldn't surprise me if it's a ford or chevy part, Kaiser/Jeep was known for sourcing the same parts used by other manufactures. It might explain the bracket. The 66 galaxy looks very similar and they seemed to have used a similar bracket:
https://www.fordmuscleforums.com/thread ... ll.651267/

This is interesting:
https://www.speedwaymotors.com/Speedway ... 96885.html


but poking around you can just select brake booster on their site:
https://www.speedwaymotors.com/shop/bra ... -474-30456

And then select on the left 'bolt hole pattern'. So you might be able to get one that works. They all pretty much work the same.

They have a location in Arizona on the west side:

8701 W McDowell Rd
Tolleson, AZ 85353
81 Waggy 'WILL E' Retired
82 Cherokee WT - SOA/SF/high steer/Alcan springs/agr box/Borgeson steering shaft/AMC 401/performer/holley TA/HEI/BeCool/727/ALTAS (2.0/2.72/5.44)/D60 Snofighter(Yukon Zip,hubs,stubs,4.56)/14 Bolt (FF,BF shave, Discs, ARB,Artec Truss)/MTR 37X12.5/Corbeau XRS Baja & 5 point retractable harness/Hella Aux lights/tuffy console/killer32 sliders/Evil Twin bumpers, rack and roll cage/WARN 8000/TT Fabworks steering brace/dual batts/custom TC skid plate/ARB fridge

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AZOutdoors
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Re: Brake Booster for a '66 Wagoneer

Post by AZOutdoors »

Great finds will e. I will through a vacuum pump on it but I think that brake movement when you shut off the engine test pretty much lets you know that it looses vacuum. I am going to pull it off and get a better look at it and take measurements and see what might be out there. I did talk to a remanufacturer today and the can do it for not too much more than a reman off the shelf will be (will take about 4 weeks).
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Re: Brake Booster for a '66 Wagoneer

Post by timwiller »

Carid has a universal one. Cardone used to have them. ...
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JWestfall
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Re: Brake Booster for a '66 Wagoneer

Post by JWestfall »

I'm in the process of installing a Summit Racing universal one on my 1971. I have it all installed, just waiting for the part to come today to connect it to my brake pedal. Had to extend the push rod to master cylinder and expand the holes on the firewall mounting bracket, but hasn't been to bad so far. Here are the parts I ordered from Summit: Wilwood Pedal Assembly Components 330-12897, Summit Racing™ Brake Pedal Rod Extension Kits SUM-760125, Summit Racing™ Power Brake Boosters SUM-760167. I hope to have it all hooked up and running this evening.
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Re: Brake Booster for a '66 Wagoneer

Post by tgreese »

Glad this is working out for you. Sounds like the hot rod sellers have a lot of parts for this and similar applications. I noticed they also sell firewall brackets that resemble the OEM brackets; this might eliminate the need to enlarge the holes of the OEM brackets, and might be helpful when converting these vehicles from manual to power brakes.

Maybe you've been documenting what you've been doing? A separate thread with a descriptive title and pictures would be a valuable resource for other owners of these earlier Wagoneers and J-trucks.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

JWestfall
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Re: Brake Booster for a '66 Wagoneer

Post by JWestfall »

Finished the install and I love it. Braking is way better than the stock booster even when it was working properly and the new booster is a little smaller diameter so changing those rear sparks plugs should be a little easier. Unless someone wants to keep there pre-74 rig totally stock I recommend this for a replacement/upgrade. Total cost was about $130. Sorry, I didn’t take any pictures.

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AZOutdoors
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Re: Brake Booster for a '66 Wagoneer

Post by AZOutdoors »

Great update. Wished I would have seen this a few days earlier as I have already sent my stock booster to a remanufacturer. I found a place that will remanufacture it for about $200.
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Re: Brake Booster for a '66 Wagoneer

Post by devildog80 »

Please keep the info handy, as I may need it when I get ready to look at brakes on mine :)
AZOutdoors wrote: Tue Aug 16, 2022 8:58 pm Great update. Wished I would have seen this a few days earlier as I have already sent my stock booster to a remanufacturer. I found a place that will remanufacture it for about $200.
'81 CJ5 Base, 258 I6, MC2100, T176 4 spd, 300 TC, D30 Front NT, 3.31, 2-Piece AMC 20 rear NT, 3.31, 4" high arc spring lift
'84 Grand Wagoneer, 401 V8 (.030 over), MC2150 HA Comp, 727 auto, Selec-trac NP229, AMC 20 REAR - D44 FRONT - WT 3.31, 4" high arc spring lift
Rather be driving, than waiting to be modified
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Re: Brake Booster for a '66 Wagoneer

Post by Harry Dawg »

Hey @AZOutdoors.
Would you mind posting a photo of your brake booster bracket?
Specifically where it mounts to the firewall. Looks like there are 4 bolts that hold it into place?
Thanks in advance.
1968 J3500 - 1985 CJ7 - 1998 Grand Cherokee 5.9 Liter Limited - 2006 Grand Cherokee Limited
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