Brake booster changing

So maybe 10-12 ? years ago I decided to change the brake booster. The MC was leaking and brake fluid naturally did a nice job of causing the paint to bubble and get all rusty/crusty. I found a NORS booster on ebay and installed it along with a fresh MC at the time. About 10 days ago I started hearing a little vacuum leak, next day I pushed the pedal down and noticed it went away... Pulled back on the pedal and all hell broke loose. Super obnoxious vacuum leak formed and only goes away partially if I push the pedal.

Front end brake servicing was already on the schedule. I was going to be doing calipers and hoses (going to the LH calipers) in addition to the rotors/pads ect. Since the booster has failed and requires the master cylinder to be disturbed I might as well just change the MC as well and call it all fresh. Pretty sure I'll be making new lines from the MC to the prop valve. I got all the nice tools for doing that now anyways... :rolleyes: I have re-made brake lines for everyone else and everything else but my own car ;)

My memory is foggy on the debate but I did order a 15/16" / 24mm master cylinder. Pretty sure that is what I have now and it seems to work. Trying the AC delco 'professional' flavor this time, it claims to be aluminum like the original chrysler unit. The current unit is cast iron.

I like the 24mm with my 11" brakes. I also like Hawk HPS as summer pads and Hawk LTS for the cold winter days such as 0F on the highway. I change pads when I change tires. If you don't want to change pads the LTS work well all year around. I purchased mine from Rich B.

I still like my ancient 14" wheels so going to the bigger brake rotor is not possible. I have been running the 60 mm piston calipers since the booster and cylinder change, not as good as the bigger rotor but a noticeable difference over the stock 54 mm calipers that everything came with otherwise. The LH calipers are a direct fit, do allow for newer pad options and are backwards compatible with the original fully captive style brake pads. The LH pads are loaded onto the caliper and then the assembly is pivoted into position. The old style servicing where you install the inboard pad, rattle clip, rotor, outboard pad and then pivot the caliper in place. If you have brake pads with those 'nibs' sticking up on the backing plate they will catch the piston and not allow the caliper to swing out without prying it off. Broken off chunks of the phenolic more than once because of that.

Fedex delivered the booster today. Typical cardone meh quality all the way... Rust pitted like nothing else where they all are just under the MC mounting bore and a nasty dip coating to replace the original flat black. Voided the pretend warranty and removed the check valve so I could degrease and do a semi proper rattle can paint job. Three coats of VHT satin black are drying right now.

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Originally Posted by 135sohc

The LH calipers are a direct fit, do allow for newer pad options and are backwards compatible with the original fully captive style brake pads. The LH pads are loaded onto the caliper and then the assembly is pivoted into position.

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OK interesting, therefore the LH caliper should also fit the 11" adapter but I am unsure of pad area etc...

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Originally Posted by chromguy

OK interesting, therefore the LH caliper should also fit the 11" adapter but I am unsure of pad area etc...

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Yes the LH calipers do fit the 11" adapter, and I am not sure of the pad area either. However they were designed for Police duty on a 4400lb car so they should be fine on our cars, and they have worked great (with Police semi-metallic pads) on my CSX for many years (91 and up spindles using the smaller rotors/adapters to clear the stock Centurions and 13" wheels for slicks).

The pad area and thickness is virtually the same. Not identical but from a performance standpoint the difference is negligible IMO.

Physically speaking the mounting points and 'external dimensions' of all the 91+ calipers are all the same. The piston size is the only difference and the adapter bracket for the bigger rotor just has a little more distance between the caliper mounting bolts center line and the center line of the two large bolts that hold it to the steering knuckle.

Got everything done today. Not too many problems, new lines from the MC to the proportioning valve were required. The old ones did not want to unscrew from the valve, snipped them off with end cutters and the impact driver took care of the tube nuts easily. Feeling lazy and I could not find my roll of bulk tubing anyways so I did buy two pre-made lines and bent them to fit.

The passenger side brake hose was still the original hose from 94 (forgot it was still original), the replacement hose of course is of Chinese origin. The irony being the driver side original hose was replaced before with a Chinese hose circa 2015. The replacement hose in the box was labeled as 'made in china' but was obvious old stock dated from 2004 and made in Mexico. Wonder how Mexico feels when they get undercut and lose industry to an even cheaper offshore alternative :lol:

385,000 miles as of now. The new old retail stock booster that failed was installed almost 10 years ago at 260,000 miles on June 28 2011 according to the records.