Parking Brake with 4 Wheel Discs

[bandhmo2]

A quick question for thous with 4 wheel disc brakes, using calipers with parking brakes. How do you like the parking brake? What I mean is does it hold well and release well?

The reason I ask is I am planing a brake setup for the YJ and looking at my choices of calipers. They are all expansive but the ones with built in parking brake have a $80 plus core charge. If the built in parking brake works well then they are worth the expanse. However, if they do not then I would prefer to save some money there to put toward a drive line brake.

Thanks,

[sourpwr]

I recently installed '77 caddy calipers on the Jeep. I still need to adjust the parking brakes, and have not used them much, yet. They still hold the Jeep on the driveway.

I picked mine up at Advanced Auto for < $100 /side. The core was only $5. Prices varied between Autozone, Napa, Advanced, and Ebay.

-- mike

[bandhmo2]

Thats not a bad price. I will start checking Autozone and others. I assumed they would all be about the same. How are your brakes as far as proportioning? Do the fronts still lockup first? I like the large Caddy calipers but fear I will have major proportioning issues.

I had planed on using front calipers in the rear with a driveline parking brake but that lead to way to much braking in the rear. I then looked at using Grand Cherokee or Explorer rear calipers but have had a hard time finding 6 lug rotors that are thin enough to work with these. I thought I had a plan to use Toyota front rotors and 80's Cadillac calipers, but then found that the Toyota rotors bolt to the hubs and so have the wrong bolt pattern.

I may just have to go to Chevy rotors and 77 Caddy calipers, as many do but would like to use smaller calipers if posible.

Thanks,

[sourpwr]

I am by no means a brake expert.

Chevy does have a smaller "metric" rear brake caliper that may work for you. You can find them on the Speedway website if you want to look at them. I'm sure that the parts houses sell them as well.

I have had my Jeep back together for all of 2 weeks and have driven it very little. I am running 3/4 ton calipers up front with the Caddy's in the rear. I do not know if my brakes are balanced at this point. Pulling off of the trailer, I am not able to lock up the rear brakes when the tires are going "over the edge". However, the fronts lock up and slide along the deck. Jegs, Summit, and Speedway, all have a proportioning block with manual adjustment for the rear brakes for about $100. I'll probably pick this up if I don't like the way the brakes feel with the stock proportioning valve.

I have run the explorer rear calipers with drum E-brakes in the rear with stock CJ7 calipers up front. The pair was well balanced, but the e-brake sucked. It worked until after the first trip out. Then I could never get the Ebrake to hold the Jeep in my driveway. But the brakes were pretty well balanced front to rear with the stock master and prop valve.

-- mike

[Rio_Grande]

My F250 disks hold really well.

As for trail rigs I have seen several that seemed to hold well.

[BMB]

I've done two rear disk conversions with six lug rotors and p-brake calipers.

The first used 91 Isuzu Trooper rear rotors and calipers. I never used the brake on them, but it should work. My axle shaft flanges had to be turned down about 1/8" for the rotors to slip on.

The second version I like much better.
I used 91 Chevy K1500 front rotors and 88 Lincoln MVII rear calipers. The rotors slipped right on with no mods and the calipers fit with no problems. I've had them on for a couple of years and they still hold quite well. For the brake cables I ordered some for an 85 Mustang SVO and hooked them to a parking brake lever from a Nissan ? mounted on my tranny tunnel cover.

BMB

[mbalbritton]

Not sure what other vehicles offer this, but the ZJ with Disc Brakes has an internal drum brake style Parking brake. I've HEARD of people adapting those to other axles. May be worth looking into.

[bandhmo2]

Thank you for the responses, I have been banging my head against the brake issue for sometime. I should have asked for help long ago.

Originally Posted by sourpwr

I have run the explorer rear calipers with drum E-brakes in the rear with stock CJ7 calipers up front. The pair was well balanced, but the e-brake sucked. It worked until after the first trip out. Then I could never get the Ebrake to hold the Jeep in my driveway. But the brakes were pretty well balanced front to rear with the stock master and prop valve.

I am glad to hear that that system was well balanced, that is why I fear running the 77 Caddy calipers in the rear. According to the Napa web page the caddy calipers are 2.5" diameter and open far enough to use with Chevy front rotors (1.285" thick). The Explorer or Cherokee Calipers are 1.81" and 1.88" respectively. Since the jeep is much closer in size and weight distribution to these vehicles, I figure they will lead a closer balance. The problem is they only open enough to fit a 0.473" and 0.43" thick rotor. And I had not such luck in finding such a rotor in the correct diameter and lug pattern.

Originally Posted by BMB

The second version I like much better.
I used 91 Chevy K1500 front rotors and 88 Lincoln MVII rear calipers. The rotors slipped right on with no mods and the calipers fit with no problems. I've had them on for a couple of years and they still hold quite well. For the brake cables I ordered some for an 85 Mustang SVO and hooked them to a parking brake lever from a Nissan ? mounted on my tranny tunnel cover.

The other common calipers are for the 79 to 85 Caddy. These were designed to only open to fit a 1.035" thick rotor as were the Lincoln Mark VII calipers (both 2.12" diameter piston). The thiner front discs from a Later CJ are this thick(the ones with the caliper mount bolted to the knuckle with 2 bolts) but they are 5 lug which did not help me.

The 91 Chevy K1500 is perfect. 1.035" thick and 6 lug, I should note there are 2 rotors for this year the "Heavy Duty" model is to thick (1.285") while the regular is correct for my use (1.035"). It never occurred to me to check these this solves a big problem.

Originally Posted by Rio_Grande

My F250 disks hold really well.

As for trail rigs I have seen several that seemed to hold well.

That is good to hear I will want a very good parking brake as I will be installing a Hydraulic winch and will need the holding power.

Originally Posted by mbalbritton

Not sure what other vehicles offer this, but the ZJ with Disc Brakes has an internal drum brake style Parking brake. I've HEARD of people adapting those to other axles. May be worth looking into.

I though about the drum type brakes but do not want to go that route. I have never had good luck with parking brakes holding and a very small drum in the center of the rotors seems like it would work even less well.


Again thanks for the help. These will go on my home brew Full float HD AMC20 so I know I will have to do a lot of custom fitting. I was actually about to give up, and go back to drums

[bandhmo2]

I think my final plan will be as fallows

Front:
78 Chevy K5 Blazer Rotors and Calipers Piston Diameter 2.6"

Rear:
91 Chevy K1500 pickup Non-HD Rotors
85 Chevy Camaro Rear Calipers with Parking Brake Piston Diameter 1.872"



Using the Proportioning spread sheet on the Pirate Web page this gives me a rear pressure reduction of about 50% needed in a proportioning valve. I cant be sure yet as I have been totally guessing as to the location of the Center of Gravity of the Jeep. However, this fairly closely matches the Pistons sizes of ZJ's and TJ's with 4 wheel discs so with a stock proportioning valve it should be close.

I could also use 85 Caddy calipers with a Diameter of 2.12 but then would need more hydraulic proportioning.

Depending on gas prices I may go to 91 chevy non-HD rotors and calipers up front as these are the low drag design and should help mileage a little. Of coarse I would also need a Quick takeup master cylinder then.