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09-13-2015, 01:06 PM | #1 |
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72 MC bore size and correct pushrod
So after much searching I went with a 1 1/8 bore size and an Oreilys part # NMC1423. But this one has a deep bore depth.
Does anyone know what MC part number would have the shallow bore depth? Trying to fix my brake issue with this $35 fix isn't as easy I though. Though mine was 1 1/4 but measured wrong. http://67-72chevytrucks.com/vboard/s...d.php?t=682026 Read I can use an adapter but Oreilys didn't know what I was talking about. thanks
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72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives) |
09-14-2015, 11:38 AM | #2 |
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Re: 72 MC bore size and correct pushrod
I am not sure of the diameter of the bore. I recall 1 inch. the way to be sure is to pull a rebuild kit off the shelf at a local parts store and see what comes in the box. Maybe the parts catologe will show some specs.
as for the short vs long.... the long push rods and the deeper holes in the back of the master cylinder piston are typical of manual powered brake master cylinders while the short push rods and shallow hole in the back of the master cylinder piston are for boosted or power brakes. the difference between short and long are considerable so you wont make a mistake there. that having been said I have made that very mistake. this distance and length too can be confirmed when you pull a master cylinder rebuild kit of the shelf for each application and look at it. Some rebuild kits dont include the replacement piston though. I hope I got that right. |
09-14-2015, 08:17 PM | #3 |
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Re: 72 MC bore size and correct pushrod
Thanks for the suggestion, I'll get by there this weekend and grab a rebuild kit and see what's in there.
I ended up slapping it back together and driving it as it. I didn't even bleed after putting the old MC back on. Actually tightened up the pedal and feels better. I just give myself plenty of room to stop. thanks
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72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives) |
09-14-2015, 09:20 PM | #4 |
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Re: 72 MC bore size and correct pushrod
1-1/8" bore is correct for power brakes on a 72 pickup.
AC Delco #18M1036 is the correct M/C. It's $44.79 with no core charge at RockAuto.com. Or you can probably cross the P/N at a local parts store. If your truck's lines and tube nuts are not stock, you may need to adapt them to the M/C. Adapters are readily available, even at some parts stores. Let me know if I can help.
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Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! |
09-14-2015, 09:34 PM | #5 |
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Re: 72 MC bore size and correct pushrod
Most excellent....Thanks Mike!
One day I'll get back to Plano...where I was born!
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72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives) |
09-14-2015, 10:35 PM | #6 |
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Re: 72 MC bore size and correct pushrod
Took a closer look at the images and looks like the pocket on AC Delco #18M1036 is too deep also.
http://www.rockauto.com/catalog/more...&jnid=4&jpid=0 After finding this thread http://67-72chevytrucks.com/vboard/s...d.php?t=668503 Looks like the 78 Corvette and other years. ACDELCO 18M91 is what I need, has a small pocket. http://www.rockauto.com/catalog/more...id=1123&jpid=5
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72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives) |
09-15-2015, 09:11 AM | #7 | |
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Re: 72 MC bore size and correct pushrod
Quote:
Here is a picture of the two types of M/Cs -- one with a deep hole for a manual brake pushrod.
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Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! |
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09-15-2015, 09:26 AM | #8 |
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Re: 72 MC bore size and correct pushrod
Yep that's what I need the one with the shallow hole.
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72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives) |
09-15-2015, 11:45 AM | #9 | |
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Re: 72 MC bore size and correct pushrod
Quote:
It is funny that I used to be a brake development engineer for GM but these things always turn into a science fair project for me, too. 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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09-15-2015, 11:47 AM | #10 |
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Re: 72 MC bore size and correct pushrod
Are you disc/drum or drum/drum?
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/ |
09-15-2015, 11:59 AM | #11 |
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Re: 72 MC bore size and correct pushrod
Disk/disk. My truck didn't originally come with power brakes. PO installed aftermarket booster/MC combo.
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72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives) |
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