GMT800 master cylinder swap problem

michael hurd said:

Likely you will not like that result either, longer pedal travel.

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On top of the already forever-like travel these trucks have from the factory.


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whiplash473 said:

On top of the already forever-like travel these trucks have from the factory.


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Having driven some of these from new, they don't all exhibit that symptom.

Many I drove had hyper sensitive brakes with OEM brake pads and shoes after a rainfall though.

Likely, long travel is a symptom of air introduced into the brake system and not properly bled out. I assure you long travel is not normal.

I was just comparing to what the newer vehicles are like compared to ours. Whenever I drive the girlfriend's '15 Xterra I just about lock them up the first time.


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I just did the abs delete on mine and have less travel on my pedal than i even feel safe with. its touchy. i bled them and man they break like brand new but i don't experienece any of the forever travel anymore, on my stock c1500 breaks.

A 3/4 ton master cylinder helps a lot

After extensive reading, using only JB6 brake components is the right answer.

slowburb said:

After extensive reading, using only JB6 brake components is the right answer.

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Ive sub'd this thread since I'm going to be doing some brake/master cylinder work on mine soon. What's JB6?


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whiplash473 said:

I was just comparing to what the newer vehicles are like compared to ours. Whenever I drive the girlfriend's '15 Xterra I just about lock them up the first time.


Sent from my bored/stroked iPhone 6S

Click to expand...

http://www.guideautoweb.com/en/specifications/nissan/xterra/s/2015/

According to this website, the '15 Xterra has a stopping distance of 41.8 meters ( 137.13 feet ) for a 4370 pound vehicle.

According to Michigan state police pursuit vehicle testing, a 1997 PPV Tahoe had an average stopping distance of 161.4 feet for a 4800 + pound vehicle.

https://www.justnet.org/pdf/michigan.pdf


In 1998, the stopping distance increased slightly. ( could be due to a number of factors )


https://www.justnet.org/pdf/93468.pdf

60-0 average deceleration on a 1998 Chevrolet Tahoe 2wd is listed as 173.7 feet.

Curb weight is 4828# without a driver from my research.



Here is a test on 2015 pickups. Not sure on the reliability of the site.

http://special-reports.pickuptrucks.com/2015/01/2015-light-duty-v-8-challenge-braking.html
60-0 of 2015 Chevrolet 1500 with 20" Goodyear Wrangler SRA was 133.7 feet.

60-0 of 2015 Toyota's big, bad TRD PRO..... 159.6 feet. Whoa... beating a 20 year old truck by a whopping 14 feet... impressive. NOT.


Edmunds:

http://www.edmunds.com/chevrolet/silverado-1500/2015/crew-cab/rating/
"Stopping distance from 60 mph was average at 136 ft."

Other vehicles just for fun:


https://www.justnet.org/pdf/2016-Model-Year-Police-Vehicle-Evaluation-Test-Book.pdf

To give some comparison to this, a 2016 Chevrolet Caprice PPV RWD with 6.0L engine was just tested.

60-0 in 130 feet. Again, better ABS system, better rubber, lower center of gravity, 2 decades of refinement in brake systems.

2016 PPV Tahoe, 5.3L 2wd, 60-0 in 135 feet.

2016 Harley Davidson electra-glide 60-0 in 150 feet.

2016 Can-am Spyder F3 60-0 in 122 feet.


I STILL stand by the fact that if your brakes are working PROPERLY, there is nothing wrong with the stopping power.

Let's stick to facts:

Switching to highway howler mud tires, or any lug / all terrain tire will increase your stopping distance.
Using no-name poor quality brake pads and shoes will increase your stopping distance.
Improperly inflated tires will increase your stopping distance.
Worn suspension components will increase your stopping distance.
Worn shocks will increase your stopping distance.
Rotors and drums that are glazed will increase your stopping distance.
Changing to larger diameter caliper pistons will increase master cylinder and pedal stroke for the same pad movement.
Air improperly bled out of the brake hydraulic system will increase stopping distance.
Brake fluid exposed to moisture will lower it's boiling point.
Servicing the hydraulic portion of the brake system on these trucks requires a proper bleed procedure.
Improperly adjusted rear brake shoes will increase your brake pedal travel.
Grooves worn in the rear backing plates will reduce the effectiveness of the rear shoes and return springs acting upon them.

^ So true.

Both of my trucks have been in the family since they were brand new and I've never thought "Man these brakes aren't good." As long as everything is maintained and bled properly they stop just fine in stock configuration. I never really understood why the GMT800 master swap gets so much love...