Spring brake upgrade suggestions.

Jay5.9L

...I just filled the cup.
Location
Riverton
The brakes in my cj have always been a little weak. I replaced the MC long ago with a Vanco kit and the axles are a D44 waggy front, Ford D60 rear semi float. Around town they are not bad but i can push through them in 4 low (4:1 and a automatic). Was thinking of giveing the system new pads, shoes, maybe drumb rebuild (wheel cylinders recently replaced).

Any suggestions for good pads etc? Should I do else other than a good bleeding? Not looking into a hydro kit just yet but it’s always a option down then road.
 

bryson

RME Resident Ninja
Supporting Member
Location
West Jordan
Is your MC sized appropriately for the non-stock brakes you're running? Aside from puddles of brake fluid on your driveway, that'd be the first thing I'd check.
 

Jay5.9L

...I just filled the cup.
Location
Riverton
No leaks as far as i can tell. The MC and booster was shot when I bought the jeep so it was the first thing that got replaced. Even with stock D30/D44 the brakes weren't amazing.
 

bryson

RME Resident Ninja
Supporting Member
Location
West Jordan
Well, if your brakes sucked with the stock axles, they are not likely to be any better (likely worse) with the larger brakes. I am certainly no brake guru, but you need to make sure you are getting the correct volume and pressure throughout the system, which means you need to match the master cylinder to the calipers and wheel cylinders . The easiest answer would be to find the specs for the MC that came in the vehicle that your axles were taken from, and find one with the same specs that will fit your CJ. There are more variables than just MC bore and stroke, such as pedal travel and ratio etc, but that's where I'd start.

All of the above is assuming that your current setup is properly bled, adjusted and in good shape.
 

astjp2

Active Member
Location
Riverdale/Alaska
Swap your front calipers to the JD8 series
Diameter (In): 3.370 Inch

they are a larger piston than a standard waggy caliper. They came on 3/4-1 ton trucks. Google it. I have the same problem and I am using a Mercury Grand Marquis master and it has a hard time holding in 4 low. If you want also goto a 614 series pads from a 1996 Chevrolet Police car, they have more pad surface than the standard D54 GM pads.
 

Jay5.9L

...I just filled the cup.
Location
Riverton
Wow that's good info astjp2. I was looking at the wilwood 2 piston calipers but most say they really don't help with stopping power. So the bigger JD8 and the pads are a bolt in? I'm running a ford disk so I could get back to the 5x5.5 CJ lug pattern if that makes a difference.


Edit: I saw a thread on another board saying you can use bigger pads from a impala on the D52 calipers. Probably the same idea.
Link
 
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Agility Customs

Supporting Vendor!
Supporting Vendor
I fought this issue with my old promod car, I was running 14" wilwood rotors with wilwood calipers and was seeing the pressures I needed to according to wilwood. I ended up swapping to a higher stall torque converter. It cured it right up and never had an issue crawling through the brakes again.
 

Jinx

when in doubt, upgrade!
Location
So Jordan, Utah
Another thought would be to turn your idle down a little so you aren't engaging the torque converter at idle...

I run stock CJ master cylinder, no-booster, with 350/700R4/Atlas combo and it will lock up my 40s... (Granted the master cylinder was bench bled like crazy before I ever installed it in the jeep :D)

I think Ryan is right you might see better results as you work with your idle/torque converter than the breaks themselves.

What Engine/Tranny combo are you running?
 

Greg

Wanderlusting
Admin
I ran a higher stall convertor in my old TJ with a 5.3, TH350 and Atlas 4.3 with 5.13 gears and 40's. IIRC it was a 1800-2000 RPM stall and it didn't crawl thru the brakes at all. I agree that the convertor is more of the issue than the brakes.
 

Jinx

when in doubt, upgrade!
Location
So Jordan, Utah
I ran a higher stall convertor in my old TJ with a 5.3, TH350 and Atlas 4.3 with 5.13 gears and 40's. IIRC it was a 1800-2000 RPM stall and it didn't crawl thru the brakes at all. I agree that the convertor is more of the issue than the brakes.
That was a mean TJ... I really liked that build.
 

Jay5.9L

...I just filled the cup.
Location
Riverton
I thought about the torque converter but it seems to do just fine around town. Running a 4.0L/tf999/D300 with 4:1/4.88/37's.
 

Jinx

when in doubt, upgrade!
Location
So Jordan, Utah
I thought about the torque converter but it seems to do just fine around town. Running a 4.0L/tf999/D300 with 4:1/4.88/37's.
When you drop it into drive in high range does it lurch forward like low range?

High Range vs. Low Range... That 4:1 changes things, more torque.
 

Jinx

when in doubt, upgrade!
Location
So Jordan, Utah
You know second thought, if he isn’t able to turn down the idle and get it his crawling more controllable, I would be curious to see if the pads would help.

While you have the front tires off doing the pads it would be worth the another half hour to do a serious gravity bleed of those front calipers. :D
 
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