Master Cylinder, Rebuild or Replace?

[hrcollinsjr]

Originally Posted by 74Opel1900 The inside diameter for the reservoir on the new MC is 21mm and the old reservoir is 24mm.

What's the measure between the two points where the resevoir 'plugs in'?

Harold

[74Opel1900]

I should have those measurements later today.

I know quite a few people need or are going to need a new master cylinder. As soon as I get the reservoir sorted out I will provide the details on where I got mine. I don't want to recommend this part if there is an issue with the reservoir that can't be resolved.

The good news is that there was no fluid in the brake booster just a lot of rust in the master cylinder so the brake lines needed to be flushed.

[74Opel1900]

Originally Posted by hrcollinsjr What's the measure between the two points where the resevoir 'plugs in'? Harold

From each of the center points it's 93mm. If anyone knows of a reservoir that may fit please let me know.

[jerseydave]

I am old school.

93 millimeters = 3.66141732 inches

[74Opel1900]

I'm being told by the seller that not all Opels have this problem with the old reservoir not fitting. Does anyone have an older (1971 - 1973) reservoir they can measure. Maybe one from an ATE Master Cylinder. I understand that older Mantas used them.

[RallyBob]

Originally Posted by 74Opel1900 I'm being told by the seller that not all Opels have this problem with the old reservoir not fitting. Does anyone have an older (1971 - 1973) reservoir they can measure. Maybe one from an AT Master Cylinder. I understand that older Mantas used them.

The older ATE master cylinder reservoirs are definitely NOT compatible with either the Delco-Moraine or the F.A.G. master cylinders. Been there, tried that!

[74Opel1900]

Originally Posted by RallyBob The older ATE master cylinder reservoirs are definitely NOT compatible with either the Delco-Moraine or the F.A.G. master cylinders. Been there, tried that!

Damn it! Ok, so I guess I have to return the part and hunt down another M/C. I was reading the thread about the GEO M/C. I may go that route unless someone has another idea (besides sending it out for reconditioning, mine is totally shot with rust on the inside). I would really like to find a reservoir that fits this one.

[BQS4]

Originally Posted by 74Opel1900 Damn it! Ok, so I guess I have to return the part and hunt down another M/C. I was reading the thread about the GEO M/C. I may go that route unless someone has another idea (besides sending it out for reconditioning, mine is totally shot with rust on the inside). I would really like to find a reservoir that fits this one.

Brian;
Here's another idea, takes some work, but, seeing as you're willing to do the Geo M/C, this would still keep it all Opel. If you can only locate a 71-73 Manta/Ascona M/C, you can swap out the brake booster from the 71-73 Manta/Ascona, it's a direct bolt up swap but, it'll allow you to use a new 71-73 M/C. I have done this a couple of times.

[RallyBob]

I modified this Strange Engineering M/C to fit a 1975 Sportwagon. Had to alter the mounting pattern a bit, make an extension button to meet up with the plunger in the booster, and alter the brake lines a bit. The bore is 1.0625", which increases the fluid volume a bit...therefore the pedal effort usually goes up. But since the car it's on is a 1975 (bigger booster), and it has the bigger 3/4" wheel cylinders and bigger 1.625" 4-piston Wilwood front calipers, the ratio works out nicely. Cost was just over $100.

The other M/C is from a BMW 320i. It has the same bore diameter and mounting pattern as a stock Opel ATE master cylinder (so it fits early Manta/Ascona), but the fluid outlets are on the opposite side. So I made some extensions for the hard lines. I tried to get a reservoir from a junkyard, but they wouldn't sell me just the reservoir. And a new reservoir from the dealer is over $80! So I got some Tilton racing reservoirs and 'made them fit'.

Both M/C's here are aluminum, so rust will never be an issue again. They can still corrode internally, but I change fluid frequently so that's a non-issue as well.

[opelwasp]

Originally Posted by 74Opel1900 Damn it! Ok, so I guess I have to return the part and hunt down another M/C. I was reading the thread about the GEO M/C. I may go that route unless someone has another idea (besides sending it out for reconditioning, mine is totally shot with rust on the inside). I would really like to find a reservoir that fits this one.

Originally Posted by BQS4 Brian; Here's another idea, takes some work, but, seeing as you're willing to do the Geo M/C, this would still keep it all Opel. If you can only locate a 71-73 Manta/Ascona M/C, you can swap out the brake booster from the 71-73 Manta/Ascona, it's a direct bolt up swap but, it'll allow you to use a new 71-73 M/C. I have done this a couple of times.

I have tried to mount the Geo M/C in the Manta/Ascona but I don't see how it can be don without MAJOR modifications. They are not similar in any way. The holes don't line up, the pushrod in the back is way too long.

[74Opel1900]

All I really need is a reservoir that fits the M/C I have. Ideally I need to find one that fits because the shop has already installed the M/C and now they are going to have to pull it. Not a huge task but it still costs money.

Bob, what's your best guess at which VW reservoir might fit? I know you said it's been a while so you can't recall but I'm willing to try. If I can find one that fits then this new M/C would be a nice option for those in need.

[RallyBob]

Damn, I just re-read this thread....I thought I had a solution for you. I found a used ATE Manta B master cylinder in my shop today, pulled the reservoir off and cleaned it with the intent to send it to you. Then I read that the center-to-center dimension of your M/C is 93 mm, with a 21 mm top inlet. The one I have is 85 mm c-to-c with 19 mm top inlets. Oh well....

As far as the VW reservoir, I truly have no idea. This happened about 1989-1990 or so, and even then I never knew the correct make/model. Smitty found an application because he had an auto parts store as well as C & R at the time, so he just started opening boxes 'til he found something that matched! I just remember he had one installed on his Sportwagon.

[jerseydave]

I saw that Bob had mentioned a VW reservoir may fit, how about a trip to a VW dealer and check out the parts department and open a few boxes and take some measurements. On one of the searches I found a forum and they steered the guy to go to the dealer and get one for a MK1 Rabbit (late 70's-early 80's)

Might be worth a try.

[74Opel1900]

Bob, I didn't take those measurements myself and it wouldn't surprise me if they were off. Don't rule out that ATE reservoir yet. If you would be kind enough to send it I'd like to give it a try. I'll send it back to you if it doesn't fit. I PM'd you my address and I'll pay for the shipping of course.

Dave, I'll try to chase up an MK1 reservoir and see if it fits. Thanks.

[jerseydave]

Brian I also saw a volvo reservoir on ebay, that is probably from the FAG company. It is a shame that they don't post the measurements for our convience in trying to find something that fits.

[74Opel1900]

Jim over at USA Opel has a brake fluid reservoir from an F.A.G. type M/C he is going to send me. I gave him the measurements and he's going to let me know if it fits. If it fits then I'll have a brand new M/C for about $100 which isn't bad...keeping my fingers crossed.

[74Opel1900]

This has turned into a real nightmare. The new M/C Jim sent has a problem and although he will gladly take a return he doesn't have any more. He also sent me 3 reservoirs (including an FAG type) but none of them fit this mystery M/C. It's been over two months since I put the Ascona into the shop. I'm going to post some pictures tonight if anyone has any ideas on how I can use this mystery M/C please let me know. I'm thinking the best solution is to find two separate reservoirs that will fit the 21mm openings so I don't have to worry about the spacing between the two openings.

[tomking]

Yes, let us see pictures.

[B-townOpeler]

Well, FWIW

I just measured ATE M/C's from my 80 volvo 264 diesel, both my 73 Opel GT's, an 83 VW Rabbit (stock VW M/C) and an 82 Mercedes 240D (stock Mercedes M/C) and every one of them had the 85 mm spacing between the holes for the reservoir. However as I am sure many of you are aware the 73 GT reservoirs only mount on the M/C with one hole and the other nipple on the reservoir is connected to the M/C via a rubber hose with a barbed plastic fitting in the M/C.

I don't see why you couldn't rig up a similar setup if you found a reservoir that would fit in one of the holes and just angle it off to the side with a hose running from the other nipple to the M/C. I also have a fiat spider where the reservoir is remote mounted and connected by hoses to both ports on the M/C. Not saying you want to copy something from a fiat but just throwing it out there.

Have not found one yet with a similar bore and mounting bolt spacing to the booster. sorry

[blancojp]

Originally Posted by opelwasp I have tried to mount the Geo M/C in the Manta/Ascona but I don't see how it can be don without MAJOR modifications. They are not similar in any way. The holes don't line up, the pushrod in the back is way too long.

You did not read the article too well, did you?

[74Opel1900]

Ok here are the pics. This fits my 1974 Ascona but the old brake fluid reservoir from the old M/C did not fit. If anyone knows anything about this part please let me know. The only markings on the part itself are the numbers 633 stamped on the bottom.

http://i250.photobucket.com/albums/g...r/IMG_2495.jpg

http://i250.photobucket.com/albums/g...r/IMG_2496.jpg

http://i250.photobucket.com/albums/g...r/IMG_2497.jpg

http://i250.photobucket.com/albums/g...r/IMG_2498.jpg

http://i250.photobucket.com/albums/g...r/IMG_2500.jpg

[BQS4]

This should work, it's an ATE, but, it's new and complete

[74Opel1900]

Gene to the rescue once again!

[74Opel1900]

Thanks to Gene my Opel will be back on the road again tomorrow. I just got the call from the shop that my car is ready and I can pick it up.