74 Manta master Cylinder

[smithrjd]

Mine is leaking at the junction with the booster, just the rear is losing fluid. Called Opel GT Source and both the M/C and rebuild kits are out of stock. Rebuild kits are coming but maybe some time. Any one have a good used M/C? or is there a different replace M/C from an other car like the GT Geo swap?

[dcm013]

Autozone shows this kit for a 74 Manta:

AutoZone.com | Shopping | Parts | Product Detail - Master Cylinder Kit (Brake)

I got a kit for my GT at Autozone last summer. Special order but it only took a couple days to come in.

Don

[timemachine]

Duane (MantAscona) knows a place in Virginia that bores and relines master cylinders with brass sleeves for not too much $$. I can't think of the name but if you search or PM him I'm sure he'll tell you.

Jim

[Gordy]

Rock Auto.com shows the M.C. rebuild kit for $12.28. I've always had good luck with them.

[RallyBob]

Originally Posted by timemachine Duane (MantAscona) knows a place in Virginia that bores and relines master cylinders with brass sleeves for not too much $$. I can't think of the name but if you search or PM him I'm sure he'll tell you. Jim

White Post Restorations....

[blancojp]

Originally Posted by smithrjd Mine is leaking at the junction with the booster, just the rear is losing fluid. Called Opel GT Source and both the M/C and rebuild kits are out of stock. Rebuild kits are coming but maybe some time. Any one have a good used M/C? or is there a different replace M/C from an other car like the GT Geo swap?

Before you do anything, take the booster out and drain whatever fluid you have inside. Make sure the inside is clean and dry before you install a new mater cylinder. Brake fluid eats your booster and you will need a replacement if not done.

I have a few Opel master cylinders in stock, some used and some rebuilt. But I believe you should consider the Geo conversion since you will have better functionality and easier to get components. As an example, you can get a Geo master cylinder on Ebay for less than $30.00 all day long. You can also use a Honda master cylinder if you are considering installing rear disk brakes in the future. Make sure the master cylinders are from non-abs cars, makes the installation simpler.

[opelwasp]

Originally Posted by blancojp Before you do anything, take the booster out and drain whatever fluid you have inside. Make sure the inside is clean and dry before you install a new mater cylinder. Brake fluid eats your booster and you will need a replacement if not done. I have a few Opel master cylinders in stock, some used and some rebuilt. But I believe you should consider the Geo conversion since you will have better functionality and easier to get components. As an example, you can get a Geo master cylinder on Ebay for less than $30.00 all day long. You can also use a Honda master cylinder if you are considering installing rear disk brakes in the future. Make sure the master cylinders are from non-abs cars, makes the installation simpler.

Unfortunately the Manta MC and the GT are not the same. The Manta MC bolt pattern is much wider then the GT and the Geo.

[blancojp]

Originally Posted by opelwasp Unfortunately the Manta MC and the GT are not the same. The Manta MC bolt pattern is much wider then the GT and the Geo.

Stay tuned, I will be installing one in my Ascona pretty soon!!!

[opelwasp]

Originally Posted by blancojp Stay tuned, I will be installing one in my Ascona pretty soon!!!

Take pics, I'd like to see how you do it.

[blancojp]

Originally Posted by opelwasp Take pics, I'd like to see how you do it.

No problem, one of my partners in crime will be doing this in detail!

[opelwasp]

Originally Posted by blancojp No problem, one of my partners in crime will be doing this in detail!

I lined up th Geo MC and the Manta boster and the bolt pattern are the same. Cool.

The only issue is the depth the Geo MC goes into the booster. I would love to see this conversion 'cause I need to replace mine and I have a Geo one availale.

[David McCollam]

The problem with the Manta/Ascona master cylinder is often not the seals. It fails or leaks due to pits in the bore of the cylinder. The M/C body is cast iron and will, or has corroded through exposure to the elements. It can even corrode if not exposed. Many people do not flush their brake system periodically and the fluid collects moisture over time.

Anyway, you can try White Post. I called once and they were right on board until I told them what it was for. They put the brakes on quick. They would not guarantee a rebore due to the nature of the passage arrangement in the Manta M/C body. There is some sort of offset fluid passage in the M/C. They will overbore the hole in sleeve and get close on the rebuild however. It is better than nothing, or at least that is how they addressed it with me.

You can call Ron Karp at Karp's Power Brake Service (909) 985-0800 and see if he ever finished any of the M/C' s I sent him. He had two or three to experiment with, but I never heard if he got a good fix or not.

Good luck,

Dave

[opelwasp]

I just found 2 kits that I will be buying. Not cheap though. Rockauto has them cheap but Gil at OGTS has had them on backorder from them for 6 months.

[neuropel]

Originally Posted by opelwasp I lined up th Geo MC and the Manta boster and the bolt pattern are the same. Cool. The only issue is the depth the Geo MC goes into the booster.

Do you have a pic of how the Geo MC fits on the booster?

[blancojp]

Originally Posted by opelwasp I lined up th Geo MC and the Manta boster and the bolt pattern are the same. Cool. The only issue is the depth the Geo MC goes into the booster. I would love to see this conversion 'cause I need to replace mine and I have a Geo one availale.

I have a booster and master cylinder which I am removing from My '72 Ascona which are both in good condition.

I don't understand what you mean by depth into the booster. I would install the Geo Mater cylinder on the booster and measure the preload if any. This is the amount you need to cut off from the inner booster stem. Once done, you can put the master in place, it should go all the way back to the booster wall with no effort. I then press the pedal and the master should move forward with little or no play.

[DennisGardiner]

Sept. 1970 to mid year 1973 the Manta uses (originally) a ATE Master Cylinder, same as the 1968-1973 GT, but with a different fluid reservior.
Booster Bolt Spacing to Master Cylinder is: 2 3/8"
{the rear piston sticks out from the master (hollow) which engages the booster rod}

Mid-Year 1973 thru 1975 (end of production) Manta used a Delco Master Cylinder, (Ie. GM standard).
Booster Bolt Spacing to Master Cylinder 3 7/16"
{rear piston is dimpled to receive the booster rod}

Note: I do not have the chassis number switch from early to late style.
If someone has it,... we can add this to our knowledge as Opel owners.

[RallyBob]

Originally Posted by DennisGardiner Sept. 1970 to mid year 1973 the Manta uses (originally) a ATE Master Cylinder, same as the 1968-1973 GT, but with a different fluid reservior. Booster Bolt Spacing to Master Cylinder is: 2 3/8" {the rear piston sticks out from the master (hollow) which engages the booster rod} Mid-Year 1973 thru 1975 (end of production) Manta used a Delco Master Cylinder, (Ie. GM standard). Booster Bolt Spacing to Master Cylinder 3 7/16" {rear piston is dimpled to receive the booster rod} Note: I do not have the chassis number switch from early to late style. If someone has it,... we can add this to our knowledge as Opel owners.

My all-original '72 wagon has a Delco M/C. I think it was May or June '72 production date.