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  #1  
Old June 11th, 2017, 18:23
jmg222 jmg222 is offline
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just got black magic brakes + new booster/MC and... no change?!?!

I just upgrade the brakes on my 1988, stock d35 with vanco's black magic 15" kit. At the same time, I had the shop replace the MC/booster with a setup from a 1995.

driving around town, I notice virtually no difference. Ok, it really didn't stop terribly, and I did go from 31" to 35" tires, so maybe there is an improvement. the reason I did all this was because on the trails, in 4lo, if I'm going down a hill (or up, and need to back down), the hill + motor idle was often enough to overcome the brakes.

Anyway, I put the truck in 4lo .. on pavement, but just driving straight, and from stop hit the brakes and gas. at around 1200-1500 rpm, not much at all, the truck overcame the brakes.

IS this normal? Is 4lo just too much for my brake setup (I have a ford 8.8 with stock drums in the rear).

I tried bleeding the brakes -- is there any trick to it? I'm terrible with brakes, but pretty sure I did this right -- Put a screw-in reservoir on top of the fill tank on the MC, filled with brake fluid, and Used a pneumatic vacuum-puller -- started with RR, LR, RF, LF. pulled like a quart of fluid.

Other than bringing this back to the shop, anything I can try myself?
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Daily drive: 2018 Jeep Grand Cherokee Trackhawk; stock (for now)

Trail ride: 1988 XJ: Motor/plumbing/electrical: 350 sbc, crane cam, holly performer intake, Terminator EFI, novak shorty headers, novak aluminum radiator; MSD ignition
Drive train: d30 front, F8.8 rear, 4.11 gears, np242 transfer case, rusty under-armor; fully locked with detroit lockers; Chevy 700r4 tranny, 35" MT's
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  #2  
Old June 11th, 2017, 21:06
Francesco Francesco is offline
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Re: just got black magic brakes + new booster/MC and... no change?!?!

Adjusting brakes may make a difference, maybe a disc swap. Make sure your prop valve isn't clogged as well. Are you sure you swapped the better booster? I'm not too familiar with the XJ ones, as I swapped a WJ one onto my MJ, but I can lock up 4 35s, and I have stock brakes in the front still.
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Old June 12th, 2017, 06:55
jmg222 jmg222 is offline
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Re: just got black magic brakes + new booster/MC and... no change?!?!

Quote:
Originally Posted by Francesco View Post
Adjusting brakes may make a difference, maybe a disc swap.
What do you mean? I'm using brand new discs from vanco

Quote:
Make sure your prop valve isn't clogged as well. Are you sure you swapped the better booster? I'm not too familiar with the XJ ones, as I swapped a WJ one onto my MJ, but I can lock up 4 35s, and I have stock brakes in the front still.
Yup.. the booster/mc on 95+ are completely different than 94 and earlier. totally different MC/res set up, and the booster is about twice as thick.
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Daily drive: 2018 Jeep Grand Cherokee Trackhawk; stock (for now)

Trail ride: 1988 XJ: Motor/plumbing/electrical: 350 sbc, crane cam, holly performer intake, Terminator EFI, novak shorty headers, novak aluminum radiator; MSD ignition
Drive train: d30 front, F8.8 rear, 4.11 gears, np242 transfer case, rusty under-armor; fully locked with detroit lockers; Chevy 700r4 tranny, 35" MT's
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Old June 12th, 2017, 07:26
Vanimal Vanimal is offline
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Re: just got black magic brakes + new booster/MC and... no change?!?!

did you bed the brakes properly?
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  #5  
Old June 12th, 2017, 07:34
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RWKHausSupply RWKHausSupply is offline
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Re: just got black magic brakes + new booster/MC and... no change?!?!

You should have used a WJ booster/master.
Did you break in (Bed) the pads, as BMB tell you to? How did you accomplish this? That did you do basically...
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Old June 12th, 2017, 07:46
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Re: just got black magic brakes + new booster/MC and... no change?!?!

I'll third the burnishing, if you don't break them in properly they never feel right.

I have the black magic pads on my xj (98 on 35's) with disc in the rear...stops better than a stock cherokee.
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  #7  
Old June 12th, 2017, 11:59
nicpaige nicpaige is offline
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Re: just got black magic brakes + new booster/MC and... no change?!?!

Brake those pads and rotors in correctly and they have more than adequate stopping power. If they changed the booster did they get the shaft length correct?
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  #8  
Old June 12th, 2017, 12:26
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lazyxj lazyxj is offline
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Re: just got black magic brakes + new booster/MC and... no change?!?!

Quote:
Originally Posted by JohnX View Post
I'll third the burnishing, if you don't break them in properly they never feel right.
I have the black magic pads on my xj (98 on 35's) with disc in the rear...stops better than a stock cherokee.
I have run 15" Vanco kit for over a decade, the last five years with Black Magic pads and I love them. The BM pads work well cold or hot.
Blaine, the owner of Black Magic, suggests running new, premium rotors, along with the BM pads, for best performance.
Do follow the break in routine as shown in the instructions.
The BM pads like to be used hard occasionally to keep them from glazing, bedding is extremely important.
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Old June 12th, 2017, 13:14
N8N_99xj N8N_99xj is offline
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Re: just got black magic brakes + new booster/MC and... no change?!?!

Did you check the rear brakes?

My '99 passed inspection for two years in a row and I thought the brakes sucked until one night the pedal started sinking on me... came to find out that one piston was froze up on each rear wheel cylinder. Redid the rear brakes (along with some finagling to actually get the self adjusters to work properly) and they were much improved after that.
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  #10  
Old June 12th, 2017, 13:51
jmg222 jmg222 is offline
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Re: just got black magic brakes + new booster/MC and... no change?!?!

Quote:
Originally Posted by RWKHausSupply View Post
You should have used a WJ booster/master.
Why?
Quote:
Did you break in (Bed) the pads, as BMB tell you to? How did you accomplish this? That did you do basically...
yup. to the T.
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Daily drive: 2018 Jeep Grand Cherokee Trackhawk; stock (for now)

Trail ride: 1988 XJ: Motor/plumbing/electrical: 350 sbc, crane cam, holly performer intake, Terminator EFI, novak shorty headers, novak aluminum radiator; MSD ignition
Drive train: d30 front, F8.8 rear, 4.11 gears, np242 transfer case, rusty under-armor; fully locked with detroit lockers; Chevy 700r4 tranny, 35" MT's
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Old June 12th, 2017, 13:54
jmg222 jmg222 is offline
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Re: just got black magic brakes + new booster/MC and... no change?!?!

Quote:
Originally Posted by N8N_99xj View Post
Did you check the rear brakes?

My '99 passed inspection for two years in a row and I thought the brakes sucked until one night the pedal started sinking on me... came to find out that one piston was froze up on each rear wheel cylinder. Redid the rear brakes (along with some finagling to actually get the self adjusters to work properly) and they were much improved after that.
Rear brakes are new also -- just finished putting in a ford 8.8.

I'm brining it down to a shop tomorrow, I'll have them check everything over to make sure.

I'll also re-do the brake in procedure. I have less than 50 miles on the brakes, so I hope if I didn't do it properly the first time I didn't cause any damage.
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Daily drive: 2018 Jeep Grand Cherokee Trackhawk; stock (for now)

Trail ride: 1988 XJ: Motor/plumbing/electrical: 350 sbc, crane cam, holly performer intake, Terminator EFI, novak shorty headers, novak aluminum radiator; MSD ignition
Drive train: d30 front, F8.8 rear, 4.11 gears, np242 transfer case, rusty under-armor; fully locked with detroit lockers; Chevy 700r4 tranny, 35" MT's
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Old June 12th, 2017, 14:47
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techno1154 techno1154 is offline
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Re: just got black magic brakes + new booster/MC and... no change?!?!

It is difficult to say with certainty whether or not the brakes are properly assembled and bled properly. Give it the once over to see if there is something that need to redone or adjusted.

You said your XJ was on 35" tires. You did not what gear ratio are in the diffs.

My XJ is fitted with JK take offs wheels and tires which are just over 32", 4.10 ratio, WJ rear disks and WK rotors fitted with OEM calipers and pads on the front. It could lock all 4 wheels on dry pavement. However, in low gear (the front diff have no driveshaft), the rear wheels will spin through the brakes and the front will drag from about 1500 RPM up. Despite the breaks on the rear wheels are good, the engine tend to push through them in low range.
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Old June 12th, 2017, 15:54
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Re: just got black magic brakes + new booster/MC and... no change?!?!

Bed teh pads in properly first.

And a WJ booster & MC does nothing over a 95+ swap. Same Master cylinder bore. I did the swap on my 2000 and experienced no difference.
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Old June 12th, 2017, 15:54
jmg222 jmg222 is offline
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Re: just got black magic brakes + new booster/MC and... no change?!?!

Quote:
Originally Posted by techno1154 View Post
It is difficult to say with certainty whether or not the brakes are properly assembled and bled properly. Give it the once over to see if there is something that need to redone or adjusted.
Yeah, that's what I'm thinking -- going to just bring it into the shop, have them do the once-over.

Quote:
You said your XJ was on 35" tires. You did not what gear ratio are in the diffs.
In the sig -- 4.11's.
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Daily drive: 2018 Jeep Grand Cherokee Trackhawk; stock (for now)

Trail ride: 1988 XJ: Motor/plumbing/electrical: 350 sbc, crane cam, holly performer intake, Terminator EFI, novak shorty headers, novak aluminum radiator; MSD ignition
Drive train: d30 front, F8.8 rear, 4.11 gears, np242 transfer case, rusty under-armor; fully locked with detroit lockers; Chevy 700r4 tranny, 35" MT's
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Old June 12th, 2017, 15:55
jmg222 jmg222 is offline
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Re: just got black magic brakes + new booster/MC and... no change?!?!

Quote:
Originally Posted by Talyn View Post

And a WJ booster & MC does nothing over a 95+ swap. Same Master cylinder bore. I did the swap on my 2000 and experienced no difference.
Yeah, that's what I thought too.
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Daily drive: 2018 Jeep Grand Cherokee Trackhawk; stock (for now)

Trail ride: 1988 XJ: Motor/plumbing/electrical: 350 sbc, crane cam, holly performer intake, Terminator EFI, novak shorty headers, novak aluminum radiator; MSD ignition
Drive train: d30 front, F8.8 rear, 4.11 gears, np242 transfer case, rusty under-armor; fully locked with detroit lockers; Chevy 700r4 tranny, 35" MT's
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