Double Diaphragm Brake Booster Upgrade - JeepForum.com
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post #1 of 8 Old 09-10-2019, 02:19 PM Thread Starter
StanF
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1995 YJ Wrangler 
 
Join Date: Feb 2013
Location: Austin
Posts: 2,446
Double Diaphragm Brake Booster Upgrade

I like to plan my upgrades well in advance...I started this way back in 2016 in this thread:
(or possibly I'm just really, really slow! )

https://www.jeepforum.com/forum/f12/...s-kit-3905097/

I haven't been real happy with my braking since forever, but I finally started an upgrade earlier this month. I'm not on stock axles - front Ford Dana 44 with disc brakes and rear Ford F150 8.8 with drum brakes.

I purchased this kit from Dave's Customs for $350:

https://davescustomsunlimited.com/je...onversion-kit/

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I also bought their adustable proportioning valve for $75:

https://davescustomsunlimited.com/ma...ibution-block/

pvc-b-2__06512.1485843519.1280.1280.jpg

I like the way that his webpage is setup for custom applications, so he gets all your axle and brake details. He even called me to discuss the bore size of the master cylinder. He recommended a 1-1/8", so I went with that. Based on what I know, I was thinking 1" or 1-1/6", but he actually told me that he would swap it out if it didn't feel right. He also recommended the adjustable proportioning valve too.

I'll add more details and pictures later, but here's some initial thoughts:

1) The same master cylinder and booster are available from many different places - Speedway, Amazon, eBay, Summit Racing, etc. The special YJ pedal rod may not be as available in some of these places, but Dave's Customs has it, and it's included in the kit. He also charges a healthy premium over the other places, but the service so far has been great.

2a) The adjustable proportioning valve made life very difficult on my 1995 because of the fitting size. The valve has a fairly typical 3/8 inverted flare. But the brake line fitting was 9/16. There wasn't an adapter that I could readily purchase to adapt it. I ended up just replacing the entire rear brake line from the rear axle up to the proportioning valve. That was easier than trying to straighten and then re-flare the stock line.

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2b) The valve also didn't come with a bracket or lines up to the MC. I made my own lines, and bracket. But Amazon and Speedway sell a "Adjustable Proportioning Valve Block, Brake Distribution System" that would have made things much easier for just a few dollars more.

61nn3nghavl._sl1500_.jpg

2c) The electrical switch in the valve is for older vehicles that don't have a pedal mounted brake light switch. In a YJ it can (and should) be removed, as it interferes with getting to the two fittings. It's a 1/8" NPT thread.

To replace the switch, I bought a 1/8" NPT plug:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

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and Loctite 545 Sealant, which is special for hydraulics:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

8185iqucxcl._sl1500_.jpg

If it feels like this is getting complicated, you are correct!

Conclusion: This valve caused a bunch of issues. There are probably better choices.

More details to come and some more installation pictures.



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post #2 of 8 Old 09-11-2019, 07:50 AM Thread Starter
StanF
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Some installation pictures and more information:

You can see the bracket and lines that I made:

img_6370-medium-.jpg

img_6371-medium-.jpg

Switch removed and plug installed:

img_6373-medium-.jpg

img_6372-medium-.jpg

The inside clip at the brake pedal was damaged when it was removed and had to be replaced - Mopar PN: 4581512AA - about $5 on eBay. I have AC, and it is really tight to reach this clip.

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I purchased the 8" booster, and it interfered with the clutch master cylinder. I thought about using a spacer at the firewall, but instead, just clearanced the booster with a 2" pneumatic sanding disc. The part that I removed is just extra material, so there's no functional problem with taking it off as I did. A 9" booster is available, but I just don't see how it would work if you have a manual transmission.

img_6377-medium-.jpg


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post #3 of 8 Old 09-11-2019, 01:37 PM
TSEJEEPERS
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Very nice and clean install.
When I did my booster set up I used a proportioning valve from a Grand Cherokee with disc brakes front and rear. They are getting harder to find. The newer ones all go through the Anti Lock brake set up.
I had a adjustable one at one time. (Old stock master and Diaphragm) It was a pain to get it set up right.

93 YJ SOA 2" springs front, XJ springs rear w/main leaf added, High pinon 9 inch rear detroit locker front Dana 44 ARB 4.56 Gears, 36 inch Irok tires too much to list.
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post #4 of 8 Old 09-11-2019, 02:53 PM Thread Starter
StanF
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One other note...before installation, I fully masked and painted the outside of the master cylinder. And used the same paint on my proportioning valve bracket. Hopefully, both will survive any stray brake fluid drops in the future.

https://www.eastwood.com/eastwood-br...y-aerosol.html

As you can tell, I didn't paint the master cylinder lid or booster - they are both the standard yellow chromate finish.
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post #5 of 8 Old 09-11-2019, 07:11 PM
paulhead
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Location: Lakewood
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Great right up Stan. I got the 95 YJ double diaphragm set up in mine, braked great with a D30/8.8 combo. I'm curious as how it'll perform with the D44 front I'm putting in.

Trying to weld has honed my grinding skills


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post #6 of 8 Old 09-12-2019, 03:50 AM
87TPIYJ
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Garage
Nice write up! And thank you for the brake clip part number. I was looking for that when I swapped my pedal assembly over and came up short. Ended up using an E clip which works but is a PITA to install.

YJUnlimited stretch, Links, SBC, Tons, Lockers, and stuff
March 2017 YJOTM/ 2017 YJOTY

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post #7 of 8 Old 09-12-2019, 08:05 AM
AZdEvilYJ
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Sub’d! This is on my to do list


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'95 YJ 2.5L
March '19 YJ of the Month!

My Build Thread

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post #8 of 8 Old 09-12-2019, 11:25 AM
NHfireLJ
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Nice work....

Good option since Nelco went off the grid... I love my braking power...
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