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#26 |
One day.....
Join Date: Aug 2008
Location: Ocala, FL.
Posts: 702
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Re: First hand experience with changing to the NBS master cylinder WOW!
No pics of your mod installed?
DZL1. |
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#27 |
Registered User
Join Date: Apr 2009
Location: Ladysmith BC
Posts: 80
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Re: First hand experience with changing to the NBS master cylinder WOW!
Me? No I just ended up buying the two MC's the new body's type and te stick one for my truck. I'm putting the stock one in today and I'm going to buy a new hydro boost next month and get it machined out that way I'll have the parts on hand next time I need to do the brakes ill swap out the new mc and hydro boost.
**i don't know if in allowed to post outside links** But here is the write up I found.... http://www.fullsizechevy.com/forum/g...r-project.html Posted via Mobile Device |
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#28 | |
Registered User
Join Date: May 2009
Location: Motor City
Posts: 9,194
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Re: First hand experience with changing to the NBS master cylinder WOW!
Quote:
Are you talking about boring out the center bore of the master cylinder (affecting line pressure)? or are you talking about the outside diameter of the hub that fits into the brake booster? K
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Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ |
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#29 |
Registered User
Join Date: Apr 2009
Location: Ladysmith BC
Posts: 80
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Re: First hand experience with changing to the NBS master cylinder WOW!
Yeah the outside diameter of the nbs master is .2" larger diameter so you need to bore out where is slips inside for the plunger to push.
It'll be a while but I'll take pictures of everything and give a good explanation Posted via Mobile Device |
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#30 | |
Registered User
Join Date: May 2009
Location: Motor City
Posts: 9,194
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Re: First hand experience with changing to the NBS master cylinder WOW!
Quote:
There were a couple different sizes used in that area; they also varied based on Quick Take up vs Non quick take up master cylinders. K
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Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ |
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#31 |
Registered User
Join Date: Sep 2013
Location: Quakertown, Pa.
Posts: 113
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Re: First hand experience with changing to the NBS master cylinder WOW!
Finally did this swap myself on my '93 Extended Cab Long bed 1500 4X4. Pedal feel was definitely higher/harder. But I feel that it still takes a firm push to achieve any kind of decent stopping power. Even with new rotors, 1 ton calipers and pads, new rear wheel cylinders and flex lines. I might have to upgrade to hydro boost next.
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#32 |
Registered User
Join Date: Jan 2006
Location: Smithfield, VA
Posts: 1,501
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Re: First hand experience with changing to the NBS master cylinder WOW!
Mickey, why don't you try a manually adjustable proportioning valve before you do anything else?
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#33 |
Registered User
Join Date: Sep 2013
Location: Quakertown, Pa.
Posts: 113
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Re: First hand experience with changing to the NBS master cylinder WOW!
Thanks for the reply, Speedy. I must say, your "Pride and Joy" is beautiful. For me, someday........ in a dream.........
My truck already has the 14 bolt rear(light duty 3/4ton), which has larger brakes than the 10 bolt rear. This was standard on my vehicle which has RPO code F44(heavy duty chassis). I thought about changing to an adjustable proportioning valve, but since my truck needed new front hardware/rotors, I figured I would go this route. I have read much here about the upgrade to bigger calipers and the NBS master cylinder. It definitely seemed like the right approach. My rear brakes are about to the point of locking up before the fronts do with the NBS master cylinder so I figured I'm close with the proportioning aspect of the brakes.
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John 1967 C20 2WD Longbed 2001 2500 HD 4X4 Extended cab long bed ![]() |
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#34 |
Registered User
Join Date: Jan 2006
Location: Smithfield, VA
Posts: 1,501
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Re: First hand experience with changing to the NBS master cylinder WOW!
Well let's relate what I read about the rear disc conversion to your situation. The disc conversion needs more pressure than the drums. So the kits usually have a new MC.
Now let's look at your set up. You have larger, MUCH larger front calipers and larger rear wheel cylinders. I think you aren't getting enough pressure. You should get the gauge kit and check each location for it's pressure. |
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#35 |
Registered User
Join Date: Apr 2009
Location: Ladysmith BC
Posts: 80
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Re: First hand experience with changing to the NBS master cylinder WOW!
Mickey, I think your going through the same problem as I am. I have a SAS and the front brakes rotors and calipers were upgraded (I'll have to look at my records to know to what exactly) my rear end felt like it was doing all the stopping and it got so bad that the brake cylinders began to leak. I put in a proportioning valve and the front is doing most the work.
I'm getting the hydro boost bored out and will be switch to the new mc soon, I just replaced the original mc and I still get a spongy brake, happen to me a couple times where it's gone to the floor. Ill gravity bleed tonight to see if that helps Posted via Mobile Device |
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#36 | |
Registered User
![]() Join Date: Jun 2011
Location: Bradenton, Fla.
Posts: 1,100
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Re: First hand experience with changing to the NBS master cylinder WOW!
Quote:
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#37 |
Registered User
Join Date: Sep 2013
Location: Quakertown, Pa.
Posts: 113
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Re: First hand experience with changing to the NBS master cylinder WOW!
Thanks for the replies guys.
My original calipers were for somewhere around 6600 lb. gross vehicle weight. These were standard on the 1/2 ton with the heavy duty chassis option. The caliper piston was around 2-7/8" in diameter. The new 1 ton calipers have pistons around 3-3/16" pistons. While pedal feel is much better, I feel the breaking could be better. Before I owned this truck, I owned an '86 1 ton pickup with hydro boost. That truck stopped extremely well. With a future upgrade to hydro boost, I'm hoping I can get similar braking to what I remember.
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John 1967 C20 2WD Longbed 2001 2500 HD 4X4 Extended cab long bed ![]() |
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#38 |
Registered User
Join Date: Jan 2006
Location: Smithfield, VA
Posts: 1,501
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Re: First hand experience with changing to the NBS master cylinder WOW!
That's odd cause I can even pull up the links you copied. Better check your computer.
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#39 |
Registered User
Join Date: Sep 2013
Location: Quakertown, Pa.
Posts: 113
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Re: First hand experience with changing to the NBS master cylinder WOW!
Links come up for me as well.
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John 1967 C20 2WD Longbed 2001 2500 HD 4X4 Extended cab long bed ![]() |
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#40 |
Registered User
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Location: Bradenton, Fla.
Posts: 1,100
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Re: First hand experience with changing to the NBS master cylinder WOW!
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#41 |
Registered User
Join Date: Jan 2006
Location: Smithfield, VA
Posts: 1,501
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Re: First hand experience with changing to the NBS master cylinder WOW!
What browser are you using?
How about now? http://www.carid.com/1998-gmc-savana...m-8666437.html crappy one ![]() |
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#42 | |
Registered User
![]() Join Date: Jun 2011
Location: Bradenton, Fla.
Posts: 1,100
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Re: First hand experience with changing to the NBS master cylinder WOW!
Quote:
Opps...... it opens now..... got it...... I'm getting it.......( AC Delco version) Thanks for your help.... |
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#43 | |
driving is in my blood
Join Date: Dec 1999
Location: Mesa AZ
Posts: 5,724
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Re: First hand experience with changing to the NBS master cylinder WOW!
Quote:
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-78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me. |
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#44 |
Registered User
Join Date: Apr 2014
Location: Colorado
Posts: 25
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Re: First hand experience with changing to the NBS master cylinder WOW!
Speedy,
Thanks for the top-notch write up, I did the MC on my 99 burb last weekend and everything went to plan. I think I want to try the larger calipers now! |
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#45 | |
Registered User
Join Date: Jan 2006
Location: Smithfield, VA
Posts: 1,501
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Re: First hand experience with changing to the NBS master cylinder WOW!
Quote:
http://www.summitracing.com/parts/ebc-usr7013/overview/ http://www.summitracing.com/parts/ebc-dp61273/overview |
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#46 |
Registered User
Join Date: Apr 2014
Location: Colorado
Posts: 25
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Re: First hand experience with changing to the NBS master cylinder WOW!
Speedy,
Well, great minds… I went to slotted rotors and green pads a while back. I remember when my rotors were regularly warped at 12k! The slotted rotors were definitely an improvement, as were the SS lines, regular bleeding and keeping the rear drums adjusted. After a trip out west through the mountains the EBC pads (mind you they had 40k on them) melted down and had sort of disintegrated a bit from the metal pad bases. I showed them to a couple of mechanic buddies and they hadn't seen anything quite like it. I think they were just toasted from the mountain roads. BTW, my rear drums are still original, I feel that's just too much of a load to put on just the front brakes. At that point I replaced the slotted rotors and green pads with the same, added the new proportioning valve (from the TSB), and was getting on with life. Small improvements overall but still a spongy pedal and some omg moments during hard braking events. I had talked with a guy years ago about some upgrades-he explained the limitations of the six-bolt options and why big brake kits sometimes disappoint owners. He was a big advocate of the bosch hydroboost- as well as the larger HD brake calipers, a straight bore MC, different proportioning valve, thicker rotors and also going up a size on the rear cylinders. I was then re-deployed and lost momentum on the project. Later, I talked with a mechanic friend about his hydroboost and although he did have better brakes, the system was prone to some leaks and his pedal was still plenty mushy. He wasn't a big fan of the expense of the project I described and that took some wind out of my sails. Talking with another GM mechanic he thought the straight bore MC idea was definitely worth a try. ...So! That's my story so far. I hope your new rotors and pads treat you well! Hopefully one day we'll get these things all dialed in... |
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#47 |
Registered User
Join Date: Sep 2009
Location: Beaverton, OR from WA State
Posts: 1,515
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Re: First hand experience with changing to the NBS master cylinder WOW!
I have been seeing this topic/procedure popping up more and more, I am very grateful that someone has figured this out and it is good to see a write-up here on it. The only thing I would change is the vague and irritating forum slang that is obs/nbs. GMT-400/GMT-800, far more accurate than some acronym that came from a forum years ago which gets edited everytime a new truck/suv platform comes out.
There is another brake upgrade that I will be performing soon on my DD, GMT-800 dual piston front calipers... ![]() ![]() ![]()
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Devin 1983 GMC High Sierra 2500, 4x4, RC/LB, 400 S.B., SM-465, NP-208, Corporate 10 bolt & 9.5" 14 bolt 1996 GMC Sierra SLE 3500 DRW, 4x4, EC/LB, Vortec 454, NV-4500, BW-4401, AAM 925 & AAM 1050 1997 GMC Sierra SLT 1500 4x4, Z71/F44, EC/SB, Vortec 350 My Introduction with my '83s History New Daily, the '96 |
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#48 | |
Registered User
Join Date: Jan 2006
Location: Smithfield, VA
Posts: 1,501
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You sometimes have to roll with what everyone else is doing
Quote:
With regard to your 2 piston caliper change. I did that after I changed the master cylinder and it made NO difference. Complete waste of time. |
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#49 | |
driving is in my blood
Join Date: Dec 1999
Location: Mesa AZ
Posts: 5,724
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Re: First hand experience with changing to the NBS master cylinder WOW!
A guy on FSC.com just posted up how to put NBS 13" rotors+dual piston calipers both front and back on OBS trucks. So friggin simple its blowing my mind.
t_graham11- the slang doesn't ever change. OBS will always be 88-98. OOBS is 73-87. NBS 99-whatever and so on. Quote:
As for the dual vs single piston debate, they only help if the single piston caliper doesn't have the power to clamp. They also spread the force more evenly across the pad.
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-78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me. |
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#50 |
Registered User
Join Date: Jun 2012
Location: melbourne, victoria
Posts: 145
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Re: First hand experience with changing to the NBS master cylinder WOW!
do you have a link to this thread?
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1988 GMC c1500 SWB D/D RHD 5.7L 700R4 |
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1988-1999, brakes, mushy, obs |
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