Master Cylinder, Rebuild or Replace?

[74Opel1900]

I'm fairly certain I have a problem with my master cylinder. I can still stop but the pedal slowly reaches the floor and I have to pump the brakes to keep this from happening. I was wondering if I should rebuild or replace the master cylinder. Here are some pictures. I'm thinking by the looks of this thing I should get a new one.

http://i250.photobucket.com/albums/g...r/IMG_2309.jpg

http://i250.photobucket.com/albums/g...r/IMG_2310.jpg

http://i250.photobucket.com/albums/g...r/IMG_2311.jpg

[hrcollinsjr]

Originally Posted by 74Opel1900 I'm fairly certain I have a problem with my master cylinder. I can still stop but the pedal slowly reaches the floor and I have to pump the brakes to keep this from happening. I was wondering if I should rebuild or replace the master cylinder. Here are some pictures. I'm thinking by the looks of this thing I should get a new one.

Replace! A sign of the M/C failing is that the pedal will slowly go to the floor but will pump up or work in a quick stop but bleed down upon steady pressure. For the trouble and not being sure whether your rebuild will work or not, I'd replace it. I use to rebuild wheel cylinders and it would sometimes take an extra one or two before I found one that the bore would clean up enough to work properly without leaking. If you have spare M/C's and want to save a few dollars go for it.

Harold

[74Opel1900]

Thanks Harold. I would like to save some money but I don't have any extra master cylinders. This car is my daily driver so I don't want to take any chances either. Is the best (only) place to get a replacement master cylinder opelgt source?

[hrcollinsjr]

Brian,
I haven't looked for a M/C in quite some time but I believe others have had good luck procuring M/C from local sources as well as online vendors such as RockAuto. They are listed as one of our vendors and IIRC give us a small discount.

The inside of your M/C may only need new seals but you won't know until you get into it. You probably don't have a cylinder hone for it so console youself with the idea that you really wouldn't save any money doing it yourself anyway and purchase a professionally rebuilt one.

Harold

[timemachine]

MantAscona and RallyBob turned me on to this place:

Brake Cylinder Solutions

Brass relines are cheaper than stainless, and they guarantee the work for life. You can call them for a quote.

You might also find an ATE master cylinder on eBay but many out there don't have the sensor for the brake failure indicator light used in the Manta and Ascona.

Jim

[kent]

I replaced mine with a new one from OGTS last month.It was 99$ with no core charge ,these are brand new with a slightly bigger internal bore and do not have the connection for the brake warning light.Seems to be working quite well and was pretty simple.

[74Opel1900]

OGTS no longer has them in stock and RockAuto only has the repair kit. There is a reman one on Ebay but they want $150 plus $15 shipping ($165)

Jim, the place you posted quoted me a price of $225 plus $20 shipping ($245). The service they are offering sounds excellent though. I'll never have to worry about replacing this part again for $80 over the price of the Ebay one. They also bead blast it and put a show quality ceramic finish on it.

How difficult is it to replace this part myself? I have the factory service manual and it says to disconnect the brake pipes and remove two self tightening nuts that connect it to the brake booster. Then to empty the reservoir and finally to remove the reservoir by removing the reservoir clips with snap ring pliers.

[hrcollinsjr]

Originally Posted by 74Opel1900 How difficult is it to replace this part myself?

Pretty straightforward especially when comparing it to a GT. In other words you can do it.

Harold

[74Opel1900]

Am I going to have brake fluid all over the place when I disconnect the pipes? Also how difficult is it to bleed the brakes after I put the master cylinder back on? I read the instructions in the factory service manual and it sounds like it's a two person job. One to press the brakes and another to bleed them.

Upon further inspection I think this brake fluid is the culprit. Looks like chocolate milk.

http://i250.photobucket.com/albums/g...r/IMG_2312.jpg

[hrcollinsjr]

Am I going to have brake fluid all over the place when I disconnect the pipes?

You can rinse it off with water.

Also how difficult is it to bleed the brakes after I put the master cylinder back on?

Not especially. Instructions usually come with the M/C.

Upon further inspection I think this brake fluid is the culprit. Looks like I neglected to check it because it appears filthy.

Didn't help for sure. Brake fluid absorbs water and should be replaced every few years to help combat rusting in the system and brake fade in heavy use situations, i.e. spirited driving, towing, mountain driving, etc.

Harold

[Mitch Manta]

Brian: I just got a new mc on Ebay for $85, shipping included, after buying a used one that I was going to rebuild. The new on is an Aisin--made in Japan. After I bring them to my mechanic, I'll see what he thinks. If you want to try and rebuild the used one I have to have ready before you take yours apart, pm me. Good luck; I have the same pedal going down issue.

Mitch

[timemachine]

Originally Posted by 74Opel1900 How difficult is it to replace this part myself? I have the factory service manual and it says to disconnect the brake pipes and remove two self tightening nuts that connect it to the brake booster. Then to empty the reservoir and finally to remove the reservoir by removing the reservoir clips with snap ring pliers.

It comes off easily as described with just a 13mm wrench for the two mounting bolts and a 10mm for the lines. If you send it in for a rebuild I would leave the reservoir on and let them reseat it, but it's not a big deal either way. I'd use an eyedropper or syringe to remove as much fluid as possible before proceeding. But the hoses are at a high point so you'll only get a few drops. I'd leave the old fluid in the lines while it's out at the shop and then bleed it when you reinstall it.

Brake fluid is very caustic to paint, so throw an old towel or rag under the whole deal before you proceed.

Old brake fluid gets really dirty but if you can pump up pressure and then the pedal sinks, it's almost certainly a bad MC (if it's not leaking elsewhere). I've gone through a few in my day.

There are attachments for bleeding brakes by yourself (or stick a hose from the bleeder valve into a jar with brake fluid already in it), but I think it's easier with two people. Bleed them in order from the brake nearest the MC first, so left front, then right front, then left rear, then right rear. Keep an eye on the reservoir fluid level and keep refilling to make sure you're not about to run out and keep the reservoir cap on between fillups or you'll splash fluid and risk getting air in the system. Once the bubbles stop and the fluid runs clear you're done.

Jim

[74Opel1900]

That's a lot of fluid for an eye dropper. Maybe I'll get a turkey baster. I'm going to attempt to do this repair myself. Is there any particular brake fluid that I should use? The factory service manual says to use Delco Supreme No. 11 or equivalent.

[sawdust]

I ordered a M/C from Rock Auto for about $25 and $10 core. The contacted me via telephone to say they did not have any in stock and asked me to send the core and they rebuilt my M/C for $25 and shipping both ways.

This was for a GT.

[Dennis Texas]

Originally Posted by sawdust I ordered a M/C from Rock Auto for about $25 and $10 core. The contacted me via telephone to say they did not have any in stock and asked me to send the core and they rebuilt my M/C for $25 and shipping both ways. This was for a GT.

that is the best deal I ever found they have rebuilt three for me so far if your core is not able to be rebuilt they charge you a 5 dollar inspection fee and return it to you. I sent brake fluid tank and all, it came back with those seals replaced as well. I doubt you will find a better deal.

Auto Parts Fast at RockAuto

[timemachine]

Originally Posted by 74Opel1900 That's a lot of fluid for an eye dropper. Maybe I'll get a turkey baster. I'm going to attempt to do this repair myself. Is there any particular brake fluid that I should use? The factory service manual says to use Delco Supreme No. 11 or equivalent.

It only takes a few minutes. If you use a turkey baster it will drip more so be careful to keep it away from the body paint. You can safely use modern brake fluid as a replacement, I use Castrol DOT 4 and you can refill your brakes for about 10-12 dollars.

Jim

[stosh562]

i just went through this with my 72 Ascona. i see you have the AC M/C. a little different from mine. when you take your M/C off, look inside the booster for any signs of fluid. if there is any in there you should definately consider replacing the booster. mine had over a pint of brake fluid in it. IF you need the booster, i have an AC one here that is used but looks to be in good shape. i could let it go for a fair price to you. outside of that, what everybody else said is good advice and the same i got when i was looking for some. i rebuilt my own M/C and found it to be very straight forward. got my kit from Rockauto. they also offered to rebuild my original at a very good price. let us know how you are doing on this.

[hrcollinsjr]

Originally Posted by timemachine It only takes a few minutes. If you use a turkey baster it will drip more so be careful to keep it away from the body paint. You can safely use modern brake fluid as a replacement, I use Castrol DOT 4 and you can refill your brakes for about 10-12 dollars. Jim

When I change out brake fluid, I use a Mityvac hand pump to empty most of the fluid from the reservoir before refilling it and starting the bleeding process. Jim's suggestion of Castrol Dot 4 is a good one IMHO. If you spill brake fluid don't worry about it, just flush the area with water!

Harold

[timemachine]

Originally Posted by stosh562 i just went through this with my 72 Ascona. i see you have the AC M/C. a little different from mine. when you take your M/C off, look inside the booster for any signs of fluid. if there is any in there you should definately consider replacing the booster. mine had over a pint of brake fluid in it. IF you need the booster, i have an AC one here that is used but looks to be in good shape. i could let it go for a fair price to you. outside of that, what everybody else said is good advice and the same i got when i was looking for some. i rebuilt my own M/C and found it to be very straight forward. got my kit from Rockauto. they also offered to rebuild my original at a very good price. let us know how you are doing on this.

Others make good points and this is also good advice. If you have been losing brake fluid but can't see any leaks under the car, you might have fluid in the booster and will need some kind of hose on your baster or something else to vacuum it out. If haven't been losing fluid, the rear seal on the MC held up and you're okay.

Hopefully you don't have to deal with taking out the booster. While the MC comes off easily, removing the booster is more of a PITA, you have to disconnect the brake pedal linkage and reach four 13mm nuts pretty high up on the firewall under the dash. It took me a while to reach the upper nuts with a long extension and universal joint on my 3/8 drive socket.

Jim

[74Opel1900]

I haven't been losing brake fluid. Not one drop of fluid hits the ground with this car. I've also checked the entire engine bay. I'm praying the brake booster is ok. You guys are starting to scare me. Now I'm wondering if the stumble at idle has anything to do with the faulty master cylinder.

[timemachine]

Originally Posted by 74Opel1900 I haven't been losing brake fluid. Not one drop of fluid hits the ground with this car. I've also checked the entire engine bay. I'm praying the brake booster is ok. You guys are starting to scare me. Now I'm wondering if the stumble at idle has anything to do with the faulty master cylinder.

Nah, don't project. Sounds like you came out on the good side on this one and can stick to plan. Be grateful.

Jim

[74Opel1900]

So I managed to get my hands on a brand new master cylinder for only $58.50 including shipping but..... the old reservoir does not fit. I'm thinking an earlier model reservoir may fit or maybe one from a GT. Does anyone have any advice based on this picture? If someone has a reservoir they think might fit and is willing to sell it please let me know.

http://i250.photobucket.com/albums/g...ercylinder.jpg

[hrcollinsjr]

It looks like a regular Opel M/C to me. How about some measurements? I usually remove good resevoirs and toss the M/C if it looks really bad.

Harold

[RallyBob]

Probably an F.A.G. (Manta B) replacement. Beck Arnley used to sell these, drove people nuts because the reservoirs are different than the Delco-Moraine M/C. IIRC, there is a VW reservoir that fits...but it's been 15 years since I've seen a new one of those M/C's, so I don't remember which model it came from.

[74Opel1900]

The inside diameter for the reservoir on the new MC is 21mm and the old reservoir is 24mm.