...sorry...another build thread...

[Bryan C.]

gravity bleeding the calipers off the mouths since I have to mount them upside down:

????

I must be missing something. Why can't you swap them from side to side to get the bleeder in the correct orientation? Is it a clearance thing?

 

[cal]

????

I must be missing something. Why can't you swap them from side to side to get the bleeder in the correct orientation? Is it a clearance thing?

I run mine on the top to keep them away from the rocks. I lost rear brakes twice that way.

 

[blondejoncherokee]

Its such a tight clearance with the leaves being so close i cant run the calipers right side up. I found out the hard way in the middle of the axle swap. I had no intentions of doing this. Otherwise the brakelines wont clear the leaves. Its crazy tight

 

[jeepme]

this may be a dumb question but can running the calipers upside down cause them not to operate properly and cause braking issues??

 

[blondejoncherokee]

No cluebut i hope not.

 

[Bryan C.]

this may be a dumb question but can running the calipers upside down cause them not to operate properly and cause braking issues??

A hydraulic system doesn't care really. Pressure is equal in all areas of a sealed hydraulic system. As long as all the air is out he is good to go.

 

[blondejoncherokee]

http://www.naxja.org/forum/showthread.php?t=1058941&page=52

post 767 shows sort of how tight it is, the issue was that I was also running the stock 77 k20 brake lines at the time, now I am running some low profile SS lines, so maybe I will try mounting them right side up now, although I am pretty sure that its still too tight, but maybe not....

 

[rockclimber]

What rear brake/front/master/booster setup do you have?

The rear end coming around is indicative of too much rear brake.

You want your bias to be somewhere between 90%:10% front:rear

 

[smokinu]

What rear brake/front/master/booster setup do you have?

The rear end coming around is indicative of too much rear brake.

You want your bias to be somewhere between 90%:10% front:rear

i was always told 70/30 split? im just asking. is this right or wrong?

 

[blondejoncherokee]

77 thunderbird calipers, 77k20 rear calipers, wj booster and master . Zj rear disc spring in the prop valve. Going to a 96 booster with a 77 metcury grand marquis master and a adjustable wilwood prop valve inline to the rear to bring down the rear braking so the rears lock up after the fronts.

 

[rockclimber]

i was always told 70/30 split? im just asking. is this right or wrong?

Maybe on a stocker. The taller you get the less stable you are going to be and the higher the chances of more weight transfer towards the front. The more front brake you want.

 

[rockclimber]

77 thunderbird calipers, 77k20 front calipers(on the rear) , wj booster and master . Zj rear disc spring in the prop valve. Going to a 96 booster with a 77 metcury grand marquis master and a adjustable wilwood prop valve inline to the rear to bring down the rear braking so the rears lock up after the fronts.

Do you know the piston sizes on those calipers? I'm not familiar with those.

 

[blondejoncherokee]

All around 3" bore

 

[blondejoncherokee]

this is the prop valve for the rear:
http://www.summitracing.com/parts/w...VpNB-d3x705ii0MiHAYHRF7YEDcJqHNHr8aAp8c8P8HAQ

I also realized my rear calipers are 2.75" and not 3" pistons.

Also, too little rear braking and you can get bad understeer going downhill, imagine going off the side of a mountain...

 

[blondejoncherokee]

Under heavy braking the fronts do up to 85% of the braking, and on some other sources online they say up to 90% of the braking, due to the weight transfer. The front end suspension compresses, the rear end comes up, the rear brakes with much less weight begin to lock up early. Add a high COG and that makes everything worse.



Here is some good reading, go to the proportioning valve section:

http://www.pirate4x4.com/tech/billavista/Brakes/

"As the brakes are applied, full pressure is allowed to the rear up to a certain point. Beyond that point, the pressure to the rear increases at a reduced rate, preventing rear brake lock up. "

its almost like my Big rear discs would help to have smaller calipers and smaller rotors . So it seems to me that massive rear brakes are not always a great thing. I might end up having to find smaller rear calipers.

I still need to drop the rear end down an 1" or two. I am thinking of raising the rear shackle mount 1/2" to 1.5" higher, whatever fits, and also maybe running a shorter shackle by 1/2" to 3/4" shorter as well. Ill see where that gets me, if thats not enough, ill try pulling a leaf out.

 

[CAJJ93XJ]

awesome! I'm gonna copy whatever you end up doing

 

[831_xj]

Good info Jon! dasswussup :gee:

 

[GordoSmasho]

One of the main reason i wanted to keep my rig as low as possible is the emergency handling on the street. It is suprisingly stable. A bit too much fun in the rain drifting with 35s onto the freeway at 2am.

Ill be interested to see what height you end up at jon. Thanks for that braking info btw. Ill be giving it a good read as im still planning out my 70/14 swap. Ill be doing a ton of brake upgrades at that time.

 

[rockclimber]

Under heavy braking the fronts do up to 85% of the braking, and on some other sources online they say up to 90% of the braking, due to the weight transfer. The front end suspension compresses, the rear end comes up, the rear brakes with much less weight begin to lock up early. Add a high COG and that makes everything worse.



Here is some good reading, go to the proportioning valve section:

http://www.pirate4x4.com/tech/billavista/Brakes/

"As the brakes are applied, full pressure is allowed to the rear up to a certain point. Beyond that point, the pressure to the rear increases at a reduced rate, preventing rear brake lock up. "

its almost like my Big rear discs would help to have smaller calipers and smaller rotors . So it seems to me that massive rear brakes are not always a great thing. I might end up having to find smaller rear calipers.

I still need to drop the rear end down an 1" or two. I am thinking of raising the rear shackle mount 1/2" to 1.5" higher, whatever fits, and also maybe running a shorter shackle by 1/2" to 3/4" shorter as well. Ill see where that gets me, if thats not enough, ill try pulling a leaf out.

Rear Brakes that big are for tow pigs

I know a number of people running 8.8 brakes on 1 ton axles with 37"-40" tires with great success.

 

[#S194]

Jon, I thought you were going to run an adjustable prportioning valve? If you are you shouldnt have to change your calipers.