Question About 73 Cj5 Brake Booster

so i found out i have a carter yf single barrel carburetor what measurement is the neck of those 5/16 in? is that the size air filter i should be looking for i measured and i think that this one is the biggest i can do with my clearance

 

Common Problem...........and before you go much further you should check your pedal ratio......as that adapter between the firewall and booster is designed offset to correct ratio and also to allow clearance in many applications due to hood or firewall clearance.........the pushrod going forward also must be fairly level as it travels through the arc created by the pedal travel.........power brake pedal ratio is about 4:1

 

Ok thanks for all the help guys my brake lights are not working now could someone tell me how the switch operates or how its triggered when the pedal is pressed if you can pictures please thanks

 

Normally a firewall mounted master has on the swing pedals inside a switch that is triggered by the motion of the brake pedal.........should be a round holed welded tab on the swing pedal bracket that accepts the switch...............or if parts of your old system are still intact..............there could be a pressure switch in line with your brake line going to the rear...........in either case there is wiring from the switch to trigger the lights to come on.

 

My switch looks like this


But since i got a new rod from the brake booster that i drilled out to match the rod from the pedal i was looking at the original and i think the hole is Slightly bigger and a bushing fits inside it im thinking i need to make the hole from the new one match the old one without the bushing so theres extra slop and it activates the switch am i correct?

 

Never seen that type of switch before...................Most that I have seen of that vintage is mounted on the bracket above the brake pedal..........take a look at the picture........the switch fits in that round holed bracket to the right of center and when the pedal is moved it completes the circuit..........when the pedal returns and is released it opens the circuit.....

 

Generally yes you are correct. The switch you have was used on '73-'75 CJ5 as well as a few other model Jeeps and AMC vehicles.

More Information for STANDARD MOTOR PRODUCTS SLS84

 

I have that exact switch in my cj and i work perfectly with the brake booster

 

Ok do you have the navajo brake system?
And what year cj5 do you have?

 

1975 cj and i use the 1987 jeep yj booster that suppose to be the same as cj had.

 

I had that exact switch in my '73 (in 1973) and my '75 (in 1975), both with factory power brakes, and they worked perfectly!

I'm not sure exactly how the switch works. There should not be any motion between the pedal and the shaft.

First I would see if I can make the switch work with it out of the Jeep, so I was sure what kind of action is needed to close the contacts. Then I would try and duplicate that action at the pedal.

Look at a switch from a '77 More Information for STANDARD MOTOR PRODUCTS SLS66 you would need to add a bracket, like the one Tarry shows.

 

Ok ill figure that part out. i found the biggest air filter for the carb i can do is 7" so ill order that so much better than the smaller one i had listed before should give me better airflow. Only problem i have at the moment is ive been reading that you shouldnt tee the vacuum port where the brake booster and pcv valve goes is this true? Maybe because you loose pressure? If so where could i obtain vacuum for the pcv valve as i will be using its port for the booster

 

In either case you need about 19-21 inches of vacuum for that booster to be effective..............get a vacuum gauge and check your options.

 

ok thanks for the info ill have to measure that. what vacuum does the pcv need to operate? what other options would i have to run it i cant see any other vacuum connections on the manifold that size. i have a 258 with carter i barrel carburetor

 

I see no other vacuum on the manifold and have read on several posts to not tee the brake booster and pcv valve. What are my options for obtaining a vacuum source other than a pump? My engine is a 258 6 cylinder and it has a carter single barrel carburetor if i do run the brake booster from the bottom port below the carb on the manifold what other place could i connect the pcv too?

 

ok guys got the brake system installed and took it for a test drive its night and day difference!! no longer do i have to stand on the brakes for it to stop its definitely a must do upgrade in my opinion i will post pictures of the complete install and brackets thanks to everyone for all your advice!!!!

 

I felt exactly the same, i did install disk brake on front along a brake booster and it feel safe to have way more power on the brake.