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Okay Guys & Gals, here's my issue. Just finished swapping a narrowed Dana60 (from a 92 Ford F350 dulley) into my 04 Rubicon. I put a crapload of cash into this conversion with all sorts of upgraded parts and it seems like it's gonna be a really sweet set-up. My offroad shop did the work and I am very confident in their work and ability to get all the details dialed in. I could not have done this level of work on my own.

I noticed right away that the brakes are quite spongy. Obviously brakes are new in the D60 front. I just put a fresh set of rotors and ceramic pads on the rear. It's a bit better but questionable in a panic stop situation. (or a steep downhill run on a trail):eek:

I get the fact that I have bigger calipers now in front. The brake fluid level is full and they have been bled a couple of times to ensure that wasn't the issue. Is the next step to modify the master cylinder to a larger size, i.e. from the F350, or is there a way to adjust the current system to increase braking capacity to a safer level?

I really appreciate your thoughts as we try to get this thing cherry before the next trail riding season starts.

Rubicon Joe
 

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Okay Guys & Gals, here's my issue. Just finished swapping a narrowed Dana60 (from a 92 Ford F350 dulley) into my 04 Rubicon. I put a crapload of cash into this conversion with all sorts of upgraded parts and it seems like it's gonna be a really sweet set-up. My offroad shop did the work and I am very confident in their work and ability to get all the details dialed in. I could not have done this level of work on my own.

I noticed right away that the brakes are quite spongy. Obviously brakes are new in the D60 front. I just put a fresh set of rotors and ceramic pads on the rear. It's a bit better but questionable in a panic stop situation. (or a steep downhill run on a trail):eek:

I get the fact that I have bigger calipers now in front. The brake fluid level is full and they have been bled a couple of times to ensure that wasn't the issue. Is the next step to modify the master cylinder to a larger size, i.e. from the F350, or is there a way to adjust the current system to increase braking capacity to a safer level?

I really appreciate your thoughts as we try to get this thing cherry before the next trail riding season starts.

Rubicon Joe
So they swapped in an axle with larger brakes and didn't swap to a different master cylinder for the brakes?

"I put a crapload of cash into this conversion"
"I am very confident in their work and ability to get all the details dialed in"

I hate to talk bad about a shop with our more details, but it looks like...
They didn't know to swap in a MC to match the front calipers, or are working you for more money.

Either way, I'd reevaluate your relationship with that shop.
 

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Discussion Starter #3
So they swapped in an axle with larger brakes and didn't swap to a different master cylinder for the brakes?

"I put a crapload of cash into this conversion"
"I am very confident in their work and ability to get all the details dialed in"

I hate to talk bad about a shop with our more details, but it looks like...
They didn't know to swap in a MC to match the front calipers, or are working you for more money.

Either way, I'd reevaluate your relationship with that shop.
Fair comment. The project did go over budget and as you know these things can just spiral out of control. I think they were trying to get me rolling without sending me into cardiac arrest.

But the MC / caliper relationship is an important one that I think should have had more discussion. I've been looking at the hydroboost option this evening, but there goes another $1200 or so as I begin to tally the parts that are recommended. Oh well, Spring is a few more paychecks away. Guess we'll have to see where this leads. Thanks!
 

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x2 on what Mr.N said.

You also need to do some searcing and reading. I wouldnt go with the E350 or Dodge MC. Here are some threads to read over to give you a start.

http://www.pirate4x4.com/forum/showthread.php?t=801560

http://www.pirate4x4.com/forum/showthread.php?t=780156

http://www.pirate4x4.com/forum/showthread.php?t=238377

I am currently running a 1.125" Durango MC with my D60s. It has a better pedal feel than the stock MC did but I think I want to try the smaller 1.0625" Durango MC to see how it feels. The Jeep is a trail rig only and so far I've only tested it up and down the street in front of the house. Still have some things to do in order to wrap up the 60s swap.

Or go hydroboost.
 

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Discussion Starter #5
frostytj,

Outstanding links. I think I'm starting to see the issues (and possible solutions) much better now. The more I learn about this stuff the more fun I'm having.:) Thanks again to all for the comments and direction.

Rubicon Joe
 

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frostytj,

Outstanding links. I think I'm starting to see the issues (and possible solutions) much better now. The more I learn about this stuff the more fun I'm having.:) Thanks again to all for the comments and direction.

Rubicon Joe
I feel your frustration my friend and I'm sure you posted here thinking that the guys in hardcore would have the most insight and thus would provide the most help... you're lucky Brad and Johnny found you first because with comments hinting to the fact that you paid a shop to do all the work without so much as a picture or a "i tried this" alot of guys in here would have made this a 3 page :mad3: thread before even getting around to the question. That's why the "non-hardcore" forum is on the board :grinpimp: No problems from me on this issue as I don't really flame, I just don't want you getting your rear charred with a question like this and ending up going to Jeep Forum for more friendly answers from now on... cause those guys would just have told you to go ask you shop what to do :) Good luck.
 

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I'm running D60's front & rear on my TJ with the stock master cylinder.
Caddy disks on the rear & Exploders on the front.
My brakes aren't spongy.
I'd suggest you take your rig to a quality brake shop - one that's been around for 30 years or so & see what they have to say.
 

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I'm running D60's front & rear on my TJ with the stock master cylinder.
Caddy disks on the rear & Exploders on the front.
My brakes aren't spongy.
I'd suggest you take your rig to a quality brake shop - one that's been around for 30 years or so & see what they have to say.
Its hard for me to believe your stock master cylinder can push enough fluid to make this set-up work with any spongy pedal ..

i tired the stock master with eldorado calipers and chevy fronts ..it stopped but sucked ..i upgraded to a dodge 3/4 van master from the local pick and pull ($12) and all is better
 

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Joe - we've had GREAT success just swapping out the MC for a dodge 2500 (and adjusting/lengthing the bolt). Done several after swapping out f/r axles and 1 ton brakes. We are usually running Chevy 1 ton calipers f/r. On my current build I'll have the chevy 1 ton's in the back on my 14b but I'm keeping the stock ford 1 ton calipers - they are huge but I expect to have no problems.
 

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I'm running D60's front & rear on my TJ with the stock master cylinder.
Caddy disks on the rear & Exploders on the front.
My brakes aren't spongy.
I'd suggest you take your rig to a quality brake shop - one that's been around for 30 years or so & see what they have to say.
So you've modified your brakes from stock? "Exploders on the front"

Did you change the caliper to Explorer calipers?
Chevy, Dodge or Ford Dana 60?
 

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So you've modified your brakes from stock? "Exploders on the front"

Did you change the caliper to Explorer calipers?
Chevy, Dodge or Ford Dana 60?
They're Dynatrac HP D60 - front & rear. The rear is an older axle I bought off e-bay. The front was bought directly from Dynatrac a few years ago.
At any rate... the brakes are not spongy & the pedal doesn't drop to the floor.
The rig doesn't stop on a dime & I don't expect it to.
 

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I have a 78 ford d60 front with a chevy 14bolt rear with caddy calipers and my brake pedal is spongy with the stock master cylinder. It WILL lock up all four tires on the highway with the 36" iroks I am currently running. It takes some getting used to, as the brake pedal has a bit of take up before they apply.
 

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They're Dynatrac HP D60 - front & rear. The rear is an older axle I bought off e-bay. The front was bought directly from Dynatrac a few years ago.
At any rate... the brakes are not spongy & the pedal doesn't drop to the floor.
The rig doesn't stop on a dime & I don't expect it to.
Do you know the front caliper it's running?

Stock or aftermarket?
Two or one pistion on the caliper?


Reason I ask, because it make a HUGE difference.
 

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So they swapped in an axle with larger brakes and didn't swap to a different master cylinder for the brakes?
So, your TJ came with a MC of 1" or 1 1/16"

The F250 came with a MC of Brake Cylinder Bore Size:1 1/16"

If it was running Chevy Brakes, it would have a MC of 1 1/4" or 1 5/16"


Just because someone dropped in a front 60 and the brakes work, doesn't mean it will with yours.
Could MC of 1" vs 1 5/16"
Or if you were lucky it could be a MC of 1 1/16" vs 1 1/16"
Even 1" vs 1 1/16" is not that bad.

Either way, you need to find out what you have an crunch the numbers. (Hint the shop that did the work should be able to tell you the numbers, but you need to double check yourself)


This all assumes that the air has been bled out of the system and everything is work well. :flipoff2:
 

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I'm running Dodge D60 front and D70 rear with stock calipers front (hugh compared to the TJ D30) and on the rear D70 it's converted to chevy K20 front calipers. I used a Dodge 2500 master cylinder. Works great.

Install was easy as pie. hooks up to the TJ brake lines without adaptors. modified the bolt on the TJ and all was good.

There is a write up on the process by Gui here on the board. Search for it.:flipoff2:
 

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Discussion Starter #18
conversion complete

frostytj

I completed the conversion using the Dodge 3500 master cylider. It was a fairly simple deal. There ARE a couple of things others should know about this so they are not surprised.

#1. The Dodge 3500 mc has a longer body than the stock TJ mc. The hard metal brake line connections move forward (away from the booster) so the bracket that holds the proportion valve (underneath the mc body) no longer slips over the two studs that mount the mc to the booster. Everything is pretty rigid under there but I'm still going to make an extension to hold the prop valve bracket securely in place.

#2. Using the spec provided in the first link (@ 1/2") extension beyond the mc face for the pushrod, I put everything together and got instantly stiffer pedal. I can now lock up all four 35" KM2 tires. BUT... the pedal is VERY stiff, like right from the top of the full pedal range. This is cool for pavement driving but I can see where I might wind up locking the brakes prematurely in a slippery, muddy downhill on the trail. Guess we'll just have to wait, see, and develop a good "feel" for how to play it. I don't think changing the pushrod extension would change anything. It's a fluid dynamics issue at this point. Maybe the Durango mc would feel a bit different.

Overall I am pretty happy with this conversion and not having to pay $1200.00 in parts for the hydroboost kit.:smokin:

Thanks again for your help.
Rubicon Joe
 

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I have K20 calipers front and rear and a Dodge Ram master cylinder(all 1500/2500/3500 are all the same).

The brake pedal "feels" good and firm but I cannot lock them up. Never really thought about this until I had to panic stop the other day. Originally I read through all the threads and everyone is "woo get the Ram MC"... and if you have retardedly big calipers I'm sure it is great, but I want to be able to lock up my 40s on pavement.

I'll probably be trying the Durango 1-1/8" master cylinder to get my braking power back.

Figured I'd add this so no one else makes this mistake.
 

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and a Dodge Ram master cylinder(all 1500/2500/3500 are all the same).
Per the online parts store... They are not all the same.

1500 has 1 1/4" (P# UP 390426 )
2500 has 1 1/4" OR 1 5/16" (P# TS 102867 ; TS 102919 )
3500 has 1 1/4" OR 1 5/16"


Calipers look close to the same but different part numbers for 1/2 to up, anyone know the piston size?




Rubicon Joe, nice followup post.

.
 
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