Booster upgrade questions

[Eagle_SX4]

I am in the middle of swapping in a dual diaphragm booster with master cylinder. 

 

The problem I have run into is the pedal height. The pedal is 2 inches higher with the new booster with the 5/16 aluminum spacer. I got the booster/master out of a 98 XJ.

 

The difference of the pushrod on the booster is only 1/2 inch. Is there a different booster I can get that this won't be a problem?

[ghetdjc320]

How are you attaching the pushrod to the brake pedal? I cutoff the old MJ booster pushrod and welded it to the 01 XJ booster I’m running and the pedal height remained the same. 

[Eagle_SX4]

7 hours ago, ghetdjc320 said:

How are you attaching the pushrod to the brake pedal? I cutoff the old MJ booster pushrod and welded it to the 01 XJ booster I’m running and the pedal height remained the same. 

I just bolted it in with out any modifications to see if it would work. Cutting and welding the booster rod was going to be the next step if I couldn't find a bolt in solution.

[Pete M]

this is likely why I see the 95/96 XJ and 99-04 WJ as the recommended swaps. 

 

https://www.motortrend.com/how-to/154-0810-cheap-jeep-brake-system-upgrades

[Eagle_SX4]

I got the booster rod modified. I cut and welded it back together with a piece of angle iron added to ensure it doesn't fail. 

 

If any one else does the dual diaphragm booster upgrade just make sure the center of the pedal mount on the booster rod is 4-7/8" away from the mounting surface of the booster. 

[Eagle_SX4]

2 hours ago, Pete M said:

this is likely why I see the 95/96 XJ and 99-04 WJ as the recommended swaps. 

 

https://www.motortrend.com/how-to/154-0810-cheap-jeep-brake-system-upgrades

I like this option better than what I did and will look into getting a 95-96 booster. I wish one of my local parts stores had one in stock so I could go and measure it to confirm proper length.

[ghetdjc320]

I tried the 95-96 booster but iirc it had slightly smaller diaphragms than the later model XJ and provided a bit less boost. I’m running the 97+ master cylinder as well since I wanted a 1” bore. I now need a 1-1/8 more as I don’t have enough fluid movement for these big brakes but the 1” works perfectly on stock brakes with the correct booster. The WJ also runs a 1” MC. The XJ setup clears the hoodline nicely though where the WJ booster needs to be flipped. 

[Eagle_SX4]

2 hours ago, ghetdjc320 said:

I tried the 95-96 booster but iirc it had slightly smaller diaphragms than the later model XJ and provided a bit less boost. I’m running the 97+ master cylinder as well since I wanted a 1” bore. I now need a 1-1/8 more as I don’t have enough fluid movement for these big brakes but the 1” works perfectly on stock brakes with the correct booster. The WJ also runs a 1” MC. The XJ setup clears the hoodline nicely though where the WJ booster needs to be flipped. 

Thanks for the info. I got the truck fully plumbed with new lines today. I will bleed it tomorrow and see how it goes with the 98 booster.

[Eagle_SX4]

I got the brakes bleed yesterday and they are working great. 

 

I was doing some more searching on Rockauto and was looking a TJ Wrangler boosters. They might be the bolt in solution I am looking for. From the pics and specs listed the only difference appears to be the pushrod that bolts to the brake pedal.

 

TJ Booster

 

XJ booster

 

Does anyone have a TJ that they could measure the booster rod?

[Htchevyii]

I bought a NOS 95-96 booster setup. It worked perfectly with a few small modifications, mostly due to the cruise and automatic transmission on the XJ.  The Bendix 9 did throw in a few extra curve balls.

 

 

 

[Eagle_SX4]

I found a 95 XJ booster in the junkyard and can confirm that the 95-96 XJ booster is the best option for the dual diaphragm upgrade with no mods to the booster rod.

 

The booster rod measures the same length as the old single diaphragm booster.

 

 

 

Also the only difference I can find between it and the later 97+ booster is the booster rod length. So if you are doing this upgrade definitely get a 95-96 XJ booster.

 

I did get my hands on a TJ booster and although the rod is much closer to the same shape as the original it is also to long and would need to be modified to fit properly.