OBS to NBS Master Cylinder Question

[magimerlin]

You went to new on the master cylinder.... you need a gmt800 master... it's Chevy 99 to 06... uses standard 9/16-20 to 1/2-20 adapter...

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[magimerlin]

Not to be "that guy" but.... the link you posted plainly said the outlet was 12x1.00, and not the 1/2-20 you where thinking about..

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[magimerlin]

Just the first one I see on this exact swap on this site.... there are ALOT more to..... pics are gone I this one thanks to photobucket by the looks of it... but the part numbers are there... and sooooo much more info..... happy reading. http://www.gmt400.com/threads/how-to-nbs-master-cylinder-swap-for-firm-brake-pedal.17998/

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[Royal Thunder]

The master cylinder I bought was for a 2007 Silverado 1500 with disc/drum which is what was in the year span mentioned in the first reply, 99-07 and mentioned in various threads. The link provided only has part numbers for the adapter, I didn't see anything for mc part numbers. That thread is the one that suggests to use a residual valve as the masters listed are for disc/disc see page 7 and the posts by knuckle dragger. Also 2005 and up is when they were changed back to drums on the rear at least that is what I read.

As for me, I did read and went to other sites as well. There was no mention of needing a specific mc as any would work as long as it was for vacuum. After finding out that is wrong I searched for a disc/drum mc and all the ones I found used hydro boost or were disc/disc in the 99-06 range. No one was able to provide a part number for what I needed help with which I won't fault anyone on. I spent hours trying to find one in 99-07 range and the one bought and returned was the only one I could find. So I am going with residual valve as the Mc I bought won't work (the m12 one) and I really don't want to keep buying mcs and hope one eventually works.

Thanks for the help though everyone. Will report back how the truck is after the valve install.

 

[superdave]

Before you do anything, have the rear brakes properly adjusted. That alone will do wonders for your pedal feel. If the shop adjusted them all the way in, then they will never self-adjust (not that they do that much anyway) and could cause noises that you are experiencing.

I did the master cylinder upgrade on mine and am happy.

 

[Not An SS]

Before you do anything, have the rear brakes properly adjusted. That alone will do wonders for your pedal feel. If the shop adjusted them all the way in, then they will never self-adjust (not that they do that much anyway) and could cause noises that you are experiencing.

I did the master cylinder upgrade on mine and am happy.

What truck do you have superdave and which M/C did you install?

 

[superdave]

Mine is a 97. Here's a link to the mc I bought.

https://shop.advanceautoparts.com/p/carquest-wearever-master-cylinder-new-mca630031/18350700-P

You do need the one brass fitting to adapt the line.

See this thread

http://www.gmt400.com/threads/how-to-nbs-master-cylinder-swap-for-firm-brake-pedal.17998/

 

[Royal Thunder]

Update on this. This was a couple weeks ago though but, still:

Installed valve and used the MC from the second thread superdave linked. Brakes are firm and peddle starts stopping the truck around 1/3 press. I tried a couple high speed stops to see if anything changed. I have yet to lock the wheels up when stepping on the brakes from a 50-55 mph stop. Takes about a 1/2 block to stop at that speed and everything on the seats will be on the floor. So it does stop good. And ABS kicks in on gravel roads when panic stopping.

Still have the clanking from the front and a low groaning sound and the occasional clank from the rear. The shop had the owner redo the rear setup and adjusted it properly and also rebleed everything. I think the front is pad walk and the rear is because I got organic pads, front are ceramic. The clanking up front only happens once and awhile. When I first started driving after the repairs it was at every single stop for the front and rear. The rear sounds like everything is shifting inside. I am hoping I didn't get the wrong pads... I can list all the parts I bought if that will help any.

 

[redfishsc]

It really sounds to me like they don't have the rear brake shoes properly lined up on the pushrods from the wheel cylinder. Speaking from experience (please don't ask lol).

I suppose having the wrong size pads would make noise, if you even could install them at all.

 

[Royal Thunder]

I just checked all the parts I bought, they are the correct ones. I have the 10" rear brakes (JB5) and bought accordingly. I forgot to mention that I have had issues with the rear brakes since I replaced the pads last year. They would stick and then when you would go from a stop you would hear a "pop" and they would break free. That is why I replaced everything back there. I even have new lines. The one thing I did notice is that I could move everything around a bit before I put the drum on when rebuilding. I noticed this when I was doing the springs. The pads would just shift. Attributed that to being drum brakes. Bought a master parts kit that had new everything (springs, pins, and self adjuster). The parking rake paw and spring were original though. I doubt that is the reason. Plus having the rear drums rebuilt twice by a shop, shouldn't that have taken car of the alignment? Could it also be that the shoes I bought have too much bite? http://www.rockauto.com/en/parts/centric,11206750,brake+shoe,1688 says they are heavy duty. I read somewhere that fleet pads/shoes are harder so they last longer.

I guess I could pop the drums off tomorrow if I have time and take a peak to check the alignment.