Flex hoses/master cylinder/calipers/bleeding

[oldroadiedog]

So I 'm rebuilding my '72 GT master cylinder. It's got scum in the reservoir. The disk brakes are sticking on both sides. I get the the master cylinder out (no easy feat) and begin disassembling it closely following the instuctions in two service manuals. I'm at the point where you push the main cylinder in and stick a tool in one of the ports to hold position and then remove the snap ring. Fine. There's a flat washer, then a rubber seal. Out they come. Then there's a white nylon washer that will not come out for #!*%. After repeated attempts I'm done. In frustration I flush the master cylinders thoroughly with clean brake fluid. The cylinder action is much smoother. Reassemble and reinstall. The brake peddle action is better but on test drive the pads are still sticking.
A. What kinda majic does it take to get that first cylinder out?
B. If it's not the master cylinder causing the sticking...would one tackle the calipers next? Power booster?

[opelgt722002]

I get the the master cylinder out (no easy feat)

One bolt can be reached easily by angling the headlight bucket halfway open and using an extension through the resulting opening. Use a towel to keep from scratching the paint.

Napa online may have rebuilt master cylinders for about $35 (unless the website is not updating). They show part # TSM
111541 (tru-stop ).

[oldopelguy]

Opels are fairly well known for having the front rubber hoses fail in such a way as to act like check valves, letting more fluid in but not letting the fluid from the calipers back to the master cylinder. It is, after all, 30 year old rubber. You may want to replace all three of the lines before you pull the master cylinder out again; they are much easier.

[Joe Van Wagnen]

after replacing the hoses it would be a good idea to totaly purge all the brake fluid....i recently put new 3/4" rear wheel cylinders in and i purged the whole system...boy was the old fluid mangy!!!! made a big difference in the brake pedal travel

[okieopel]

Same thing happend to me at 55mph (state road don't ya know). Replaced both your brake hoses, not just one side. Better get the back single while you are at it.
Remember to bleed your brakes every year
until you get to the clean fluid. Nothing stops like clean fluid.
I'm sure RacerBob and RallyBob are with me on this.
,Dan

[oldroadiedog]

A guy would be able to confirm bad brake hoses by disconnecting at the caliper, putting the loose end in a container with fluid and then pumping the peddle to see if fluid is drawn back into the hose...right?

[okieopel]

Sorry the answer is no.
You will not be able to tell if you old hose is kaput by doing a simple bleed test.
When a hose collapse on the inside it is difficult to tell. One day they may work fine, and the next day while you are taking a left turn your caliper locks up. These things have a good amount of pressure running thru them. After all they have to stop the car.

If your hoses are old then replace them. Napa and OGTS sell them at a resonable price compared to the expence of not replacing them and smacking the nose off your car.

[oldopelguy]

The only good way I've ever found to test the hoses is to disconnect both ends of each hose and throw them away. Install new ones, bleed brakes, and see if the problem is fixed.

Really, this is almost as common/serious/important as replacing the rubber wiring in the headlights. I would place it higher on the importance scale than even the Weber carb or Pertronics ignition.

Who cars how fast the car can accelerate when it is going right into the back of a truck?

[oldroadiedog]

As suggested both brake hoses were replaced today. The front pads are still sticking although the brake peddle action has improved again. I just ordered rebuilt calipers which I should have installed this time next week. This weekend I'll paint wheels and get new tires Monday. I'm doing everything I can to help float the U.S. economy.

[okieopel]

It can sting sometimes. Make sure you have plenty of fresh brake fluid on hand to bleed the holy hell out of your brake system.

Start with clean fluid in the reservoir by drawing out the old fluid with a large syringe from the local Feed and Seed/Veterinarian Supply store and a piece of vacuum hose.
Then fill the reservoir with fresh fluid.

Next bleed the system by opening one bleeder screw at a time. Drawing out the old fluid with that same large syringe and vac.tube.

Start at the back of the car. Draw the old fluid out untill you get fresh clean fluid and empty the full syringe into a used oil container. Repeat for each wheel.

Cheers.

[baz]

hi all i would have thought that on any sticking disk the first thing to pull would have been the calliper.as you get ware on the rubber rings that seal the pistons they don't pull the pistons back into place and your brake pads then bind
when you bleed the whole systom you should start at the front drivers side (shortest pipe) then the front passenger side then go to the rear finnishing with the cylinder with the longest run this way any air or old fluid cannot get pulled back into apipe nearer the master cylinder

[kwilford]

Well, I thought I knew the answer to this, which was to start at the wheel farthest from the master cylinder, and then work towards it. Which I learned in High School Auto Shop class in 1974, so I thought I should look it up, in case things had changed, or (perish the thought) I had muddled up the order in the past 29 years. And bled my brakes incorrectly at least 10 times during that period

But my Chilton's Opel manual says to only do this if all the brakes are "drum" style; otherwise it says to start with the disc brakes first. Hmm, didn't we have dick brakes in 1974? Well, not on my '61 A-H Bugeye Sprite, so at least I didn't screw THAT up.

But the FINAL authority (short of RallyBob) is the official Opel Factory Service Manual. Both of mine ('71 and '72) as well as my Autobooks Opel Manual agree: Bleeding should start at the wheel closest to the MC, and then progress outwards (no matter if it has dual circuits or not). And do only one wheel at a time, ensuring that the MC reservoir never depletes, and filling it after each wheel is bled.

The end.

[okieopel]

Yep. Baz and Kwilford are right. Start at the front.

[opelgt722002]

Just received the rebuilt master cylinder for $34.99 from Napaonline. Can't beat the core price of $1.11 either. My rebuild kits cost me more than this.