SLH Brake Upgrade?

[85shelbycharger]

Ok, I've been into TM's for a while now (5 years or so) and have heard about this package, but never actually retained anything I read about it. So my question is this: what does this upgrade consist of exactly? I am towing home an '89 Turbo Mini parts van this week, and was wondering if everything needed for this upgrade is on the van? THanks!

[edglock21]

I'm not sure if you've seen these two articles or not, but I've read thru them a few times and they seem to have a lot of info regarding the SLH upgrade:

http://www.xmission.com/~dempsey/shelby/slhpkgs.htm

http://minimopar.knizefamily.net/perf/brakes.html

Hope this helps, I'm sure you'd like so first-hand knowledge too though. :)

[iTurbo]

I've run a variety of the SLH setups on my GLH Turbo. When I first upgraded the stock brakes, I had went with an entire brake system from my Shelby Lancer, which consisted of 54mm single-pin KH calipers for the front and a 10" solid rear disc setup. I had upgraded my SL to the 11" vented setup from a GTC, so the GLH got the hand-me-downs. The braking was worlds better than the stock setup, but that was mostly because one of the rear wheel cylinders in the drums was leaking badly. With this setup, I used the 24mm master cylinder and the prop valve from the SL.

I then rebuilt the entire chassis/suspension/steering/brakes on my GLH, and upgraded the brakes again. This time I used Caravan calipers with 60mm stainless steel pistons and the 11" rear vented setup with 36mm stainless steel pistons from another GTC. For this setup, I continued to use the 24mm master cylinder, and a prop valve from the GTC. Braking is better than ever for most driving situations, except when I really push the brakes the rears tend to lock up prematurely. Hard braking in a straight line can lead to fishtailing. Hard braking around corners can initiate over-steer, especially on wet roads. I would stay away from the 11" vented rear setup on an L-body. They are just too light in the rear. I suppose it could be dialed in better with adjustable prop vavles, or by experimenting with different stock prop valves though.

If you want the Caravan front brakes, you'll need the calipers, caliper mouting brackets, and most likely the rotors as well. The rotors are essentially the same as the stock GLH rotors, except the vane spacing is slightly narrower on the Caravan rotors. I found that the Caravan calipers wouldn't work with the GLH rotors. The GLH rotors were too thick for the Caravan calipers with new pads to fit over.

If I had to do it all over again, I would use the Caravan front calipers, and a 10" solid rear disc setup. Use the prop valve from a 10" rear disc car, and a 24mm master cylinder.

[MoparN75]

Question about master cylinders....I understand that when converting mm to in the 24mm is 0.9520799999999999. So am I to assume that master cylinder needed will have a 1 embossed on the top of it as opposed to 7/8? Reason I ask is because that is what the SC have on them and having upgraded to Caravan calipers I have a hard pedal and can't lock the brakes up with all the force I can muster. Something not right but I don't know what it is. The Lebarons have the 1 on their mc until you get into the newer model which have 7/8. Any help would be appreciated.

[cordes]

The 24mm MCs have a 24 stamped on them.

[MoparN75]

24 or just 4 like some of the Caravans, Shelby Daytonas and Lebaron GTCs? I've seen a few with the 4 and that is what I put on my Lebaron when I upgraded to the Shelby Daytona brakes front and rear.

[iTurbo]

All the 24mm MCs I have seen had a '4' cast into the snout. A 21mm unit would have a '1' cast into the same spot.

[turbovanman²]

Question about master cylinders....I understand that when converting mm to in the 24mm is 0.9520799999999999. So am I to assume that master cylinder needed will have a 1 embossed on the top of it as opposed to 7/8? Reason I ask is because that is what the SC have on them and having upgraded to Caravan calipers I have a hard pedal and can't lock the brakes up with all the force I can muster. Something not right but I don't know what it is. The Lebarons have the 1 on their mc until you get into the newer model which have 7/8. Any help would be appreciated.

The MC is not your problem. The smaller the bore, the less fluid you have so the pedal will be soft/spongy so to speak if its too small. IF you have a hard pedal, your brake booster isn't working properly. Going to large with an MC will give you too hard a pedal also.

[MoparN75]

Okay, I preformed this simple test and the pedal dropped when engine was started.
*To check the vacuum booster, pump the brake pedal with the engine off until you've bled off all the vacuum from the unit. Then hold the pedal down and start the engine. You should feel the pedal depress slightly as engine vacuum enters the booster and pulls on the diaphragm. No change? Then check the vacuum hose connection and engine vacuum. If okay, the problem is in the booster and the booster needs to be replaced.*

This car sat for a number of years and its had this problem sense putting it back on the road a couple years ago. When I put it back on the road I installed mini van calipers on it that I'd had on my Lebaron, {they worked very well in that application, and that with the stock master cylinder}. Brakes work... okay for everyday driving but nothing like they should, not as good as the originals. With all the effort I can apply I can't lock the brakes up. This is an '87 Shelby Charger, in case I hadn't mentioned that. It was converted to T2 many year ago and I'd like to re-install the I/C and let the GLHS stage 2 computer control the boost but with the brakes like this I'd never get it stopped....and that aint good.;-}

[Force Fed Mopar]

Another good thing to do is make sure you flush the entire system out, so it has good clean brake fluid in it. I did this when I did the SLH3 swap on my GLHS, you wouldn't believe how much crap came out of the system. This is especially important when using junkyard calipers and masters.

I like the SLH3 setup ('89 minivan 14" front calipers/brackets, stock GLHS 10.25" front rotors, 10.25" solid rear rotors and calipers off a Lebaron, prop valve & master from same Lebaron). Worked great on our last mountain run, even with cheap pads and AutoCrap brake fluid, I could run hard on the downhill for 15-20 mins before I started getting brake fade and brake fluid overheating.

I think w/ some SVT brake fluid and some Green Stuff pads, SLH3 is all you need except in extreme apps.

[turbovanman²]

Hmmmmmmmm, are you getting 18-20 inches of vacuum to your booster? You should still be able to stop, but a mushy pedal. I would jack up the front wheels, then start the car, spin each wheel and have a buddy put on the brakes slowly and compare that both front wheels lock at the same time. If not, the prop valve could be bad. If they do, then yeah, the M/C is no good.

[MoparN75]

I changed mc to the 24mm unit pedals harder but still it isn't braking properly. I've definitly got something else wrong here. Booster is good, the problem is somewhere else. Guess I'll have to check proportioning valve and check for any restrictions. As I dig into this thing I think I'll go ahead and replace any old/questionable parts.