To much stopping power??

[cozdude]

Is that really a thing? Can there be to much stopping power?

So long story short I’m in need of a new master cylinder for my JK (Brake fade, pedal drop, etc). So was looking at just getting a new master cylinder off of rock auto or Quadratec. Then I started to think that if my master is leaking into the booster that I’m going to need a new booster as well. This puts the cost right up around $200 if I need both, or just the master is $80-$100.

So that got me thinking about the JK8 kit. The kit comes with the bigger master and new booster. I can get the kit from my friend at the dealer at his cost which is about $225.

Now for the question. I have pro grips. Will adding this jk8 kit provide “to much” braking power? Does anyone have this combo? I heard that this swap isn’t needed for 37’s and under. Also me overthinking things, I’m thanking it might be to much since I have a 2 door on the light side of things. Knuckles only weights 5200lbs.

Thoughts?

 

[Snboarder113]

You won't have the same pedal travel, thats to say less input causes more grab then you have now. Might make it feel a little touchy, might not be that big of a difference.

 

[cozdude]

You won't have the same pedal travel, thats to say less input causes more grab then you have now. Might make it feel a little touchy, might not be that big of a difference.

Right, the bigger master pushes more volume with less travel and effort. I’m wondering if since the pro grips already increase the stopping power if this addition would more or less be overkill?

 

[Snboarder113]

Right, the bigger master pushes more volume with less travel and effort. I’m wondering if since the pro grips already increase the stopping power if this addition would more or less be overkill?

I don’t think that’s going to be something you can figure out without just doing it and finding out. It’s got ABS and all the fun electronics to stop you from locking too hard. But the feel and travel of the pedal could honestly go either way. I don’t think there’s a reason ‘not’ to do it could feel grabby or could feel luxurious like you don’t have I work as hard. Also have you been happy with your braking already? Does it need to be improved?


Sent from my iPhone using WAYALIFE

 

[highoctane]

My ‘15 JK had the extreme duty brake package on the Dynatrac XD60/PR80 axles. IIRC it’s basically Ford E350 van rotors and calipers up front (14” rotors and twin piston calipers) and J8 military Jeep rear brakes. I ran the stock booster and master cylinder. It would stop hard when you needed to, and I never thought it was too much under normal braking. That Jeep was heavy though, and really needed it with the heavy weight and 40s.


Sent from my iPhone using WAYALIFE

 

[Brute]

My ‘15 JK had the extreme duty brake package on the Dynatrac XD60/PR80 axles. IIRC it’s basically Ford E350 van rotors and calipers up front (14” rotors and twin piston calipers) and J8 military Jeep rear brakes. I ran the stock booster and master cylinder. It would stop hard, and I never thought it was too much. That Jeep was heavy though, and really needed it with the heavy weight and 40s.


Sent from my iPhone using WAYALIFE

I have the exact same brake setup with a lighter Jeep on my JK6 (I believe at 5300 lbs)...it does not feel over braked and certainly not overly pedal sensitive...

 

[highoctane]

I have the exact same brake setup with a lighter Jeep on my JK6 (I believe at 5300 lbs)...it does not feel over braked and certainly not overly pedal sensitive...

I loved those brakes. I edited my post a bit. It stopped hard when I needed to, but was perfect under normal braking.


Sent from my iPhone using WAYALIFE

 

[Eugene the Jeep]

I just installed the crown big brake kit with the Mopar JK8 master cylinder and booster on my JKU with 37's. The difference from stock to the new kit is amazing.
There is a lot less brake travel and quick brake response. It take a little bit to get use to the new brakes.
The only issue I have after installing the new brakes is that the primary brake line from the new master cylinder to the ABS pump started to leak at the master cylinder.
The brakeline from Mopar is on indefinite back order and the only ones in stock at dealerships are fro customer repairs.
Hope this helps.

Sent from my SM-N975U using WAYALIFE mobile app

 

[Ddays]

Knuckles only weights 5500lbs.

^^ Correction

The pedal travel comment makes sense. Gruff weighs 5900 so I don't think there will be any issues

 

[cozdude]

My ‘15 JK had the extreme duty brake package on the Dynatrac XD60/PR80 axles. IIRC it’s basically Ford E350 van rotors and calipers up front (14” rotors and twin piston calipers) and J8 military Jeep rear brakes. I ran the stock booster and master cylinder. It would stop hard when you needed to, and I never thought it was too much under normal braking. That Jeep was heavy though, and really needed it with the heavy weight and 40s.


Sent from my iPhone using WAYALIFE

I have the exact same brake setup with a lighter Jeep on my JK6 (I believe at 5300 lbs)...it does not feel over braked and certainly not overly pedal sensitive...

Thanks guys. Good to know the stock set up is more than enough for you guys. I will just stick with the stock master cylinder