WTB AC Delco # 18M1036
 

I need a new AC Delco part# 18M1036 Master Brake Cylinder pictured.
AC Delco has changed the design style of the part from the older OE replacement style pictured. They have not changed their web photos or packaging.
Web site offerings are not offering this older OE style.
Thanks for any info, help or leads.

Re: WTB AC Delco # 18M1036
 

brand NOS master cylinder in factory oe replacement version----127.38 shipped.paypal or postal M.O accepted.ships from NM.

Re: WTB AC Delco # 18M1036
 

PM sent.

Re: WTB AC Delco # 18M1036
 

I have this one from one of my 71 k5.its not acdelco or part number but new and finish related.lmk

Re: WTB AC Delco # 18M1036
 

Unfortunately not what I am looking for.
This very accessible and common style is what AC Delco has replaced the OE master brake cylinder that is shown in my original post.

Thanks for posting and good luck with your sale.

Re: WTB AC Delco # 18M1036
 

No problem and glwys.

Re: WTB AC Delco # 18M1036
 

Have you found a master cylinder? I have an original delco-morraine that I bought for my 72 C20 and sold the truck. LMK Thanks, Dan

Re: WTB AC Delco # 18M1036
 

Dan,
I have not found the original style master yet that I’m trying to replace.
Even NAPA and the other auto stores don’t even carry this original style anymore.
NAPA’s offering is identical to the newer AC Delco replacement with the same stamping China made.
Their web site/computer photos have not been updated and show the older double bail style but when you open the box it has been replaced with the newer single bail resevoir.
Frustrating and shame on AC Delco ;)
I can’t understand that a replacement or rebuilt older style part is not available.
What style is your C20 master cylinder?
1” deep bore?
Part number and photos would be appreciated.
Thanks for your response

Re: WTB AC Delco # 18M1036
 

Having just gone though the replacement of a master cylinder of a 70 C20 that took 3 different/remanfactured master cylinders to get one that worked I am recommending you get your current one sleeved and rebuilt. The three we had were from different vendors but once you opened the box there was no discernible difference in them. Same castings, same paperwork. New or remanufactured no difference.

Re: WTB AC Delco # 18M1036
 

Still being patient to locate this elusive style master cylinder.
I have a couple of folks checking for me.:smoke:
As you stated, the last resort would be to rebuild my existing master and the OE cast iron proportioning valve.
Pricey? Yes, but the 72’ would be good to go for another 52 years! ;)

Thanks

Re: WTB AC Delco # 18M1036
 

I have this Master Cylinder that I bought new 20 or 30 yrs ago.

All it has done is sit on a booster attached to my 55.1 GMC100.

It has never been used. Don't know exactly if it is what you are looking for.

My project took a different turn and this master is up for grab's.

Re: WTB AC Delco # 18M1036
 

Sorry for the delayed response JDarby I have been away for a bit.
Thanks for the offer but I finally located an older style master cylinder replacement….finally!:lol:
Thanks again

Re: WTB AC Delco # 18M1036
 

Did you locate a new dual bail ACD like the one I found?

Re: WTB AC Delco # 18M1036
 

Not a new one but I located a remanufactured AC Delco (style) from old stock Wearever Parts. If you order a new Wearever brake master cylinder nowadays it will be a single bail.
The EBay seller you offered didn’t have another old stock master cylinder.
I think you got the last one!:metal:
It still boggles my mind that the double bail style is not available anymore. :(
Hopefully the install and functionality test will go well on this unit.;)

Re: WTB AC Delco # 18M1036
 

Any results?

Re: WTB AC Delco # 18M1036
 

I found a remanufactured master on eBay but have not done the install yet.
Other priorities lately have delayed the swap.
I really wanted a true AC Delco double bail unit but no luck locating one.
I am still debating whether I should just get the Corvette style Master Cylinder and a matching Proportioning Valve for an updated swap.
Just wanted to stay as close to original as possible.
My brakes presently work but maybe only 80% pedal feel of what it was before the trucks restoration.
I’m confident that a new Master and a brake system bleed will get the brakes back to 100%.
I’ll post the outcome soon.
Thanks for the reply.;)

Re: WTB AC Delco # 18M1036
 

I will double post this here and on the main forum posts to hopefully get more input from site members.
Just a follow up on my Master Cylinder dilemma and swap.
With help from a friend we swapped out the OE master cylinder with the new bench bled master, checked the correct gap for the long piston between the booster and the master ( 1/16”+ gap before pedal activation), and then bled the system starting at the right rear drum, left rear drum, right front disc then the driver side disc.
After a test start up to check for leaks I took it for a test drive only to have the same previous hard pedal condition. Could not lock up the brakes.
I did need to replace the master due to age and a little corrosion but now the focus is on a new faulty (less than 100 miles) POL Power Brake Booster.
I did the two pedal tests and it failed both.
I then ran the engine for a few minutes, turned it off and 30 seconds later unplugged the power booster check valve.
No hissing or escaping air at that point. Booster check valve tested good.
I then got a vacuum gauge to the carburetor vacuum line and found 16 in. Hg of vacuum. I believe and hope that this is good enough vacuum.
So after every said and done, turns out I may have a brand new faulty POL Power Brake booster. I have heard that others have had brand new bad booster issues out of the box.
I will call POL on Tuesday and see what they have to say.
I may just go with my OE original functioning black painted Delco Moraine power booster and forget the pretty Cadmium plated after market market booster. :lol: no more bling! ;)
I love working and learning about my truck. :metal:
Any advice and input would again be appreciated.
Thanks all,
Sam