New front brakes but no fluid, back brakes are fine

[Texsardo]

Working on friends 77Spider. Her passenger front brake was locked down. PO had put something like glue on piston and pad. Well, I have replaced both sides on front : wheel bearings, calipers, pads. Brake lines are good and pliable. Bleeding system.... r rear good L good but no fluid to front brakes. Since lines look good I am thinking master cylinder. It is grossly rusted and looks worse than the Titanic' s anchor. So thoughts?

[rridge]

It's a fussy job but the flexible brake lines should be replaced every ten years or so regardless of mileage. There's no way to determine by looks whether the rubber has swelled internally and if they have not been bled on a regular basis the new fluid can swell and attack the old rubber. Of course the same is true of the master cylinder seals. The "glue" used on the back of the pads was probably anti-squeal compound and yes, its does function a bit like glue but should release again depending on its age.

[courtenay]

If the piston in the master cylinder is partially compressed (I.e. stuck). Fluid will not flow to the front brakes, but will to the rears. I learned this when I replaced my booster and had the plunger coming out of the booster too long so that it was partially compressing the MC piston. I’d replace the MC...not expensive and a fairly easy job.

[Texsardo]

Records on car show "brake job done in 2010" Calipers looked good all around. Pads in back had minimal wear. So didn't change them out. Braked and held firm. All back together, then pulled front. Calipers looked shiny new, flex hoses front and back looked not very old, supple, no compressed areas. Removed left caliper and it was froze. Had to get screw driver and wedge in to finally loosen pad enough to remove. Red substance was glued to back of both pads. And blessed was broken off just below flush. This car set for years I think after work was done. P O had all kind of repair shops do work and none specialized in foreign cars. . I have never seen so much crap done to a Spider. So new front axle bearings, calipers, pads. No fluid as I previously wrote. Pumped about 5minutes and disconnected the hoses and no fluid.
I am ordering New master cylinder as I can't think of anything else. I will reply with results of new MC.

[18Fiatsandcounting]

And blessed was broken off just below flush.

I'm guessing that this is the autocorrect version of "And bleed screw was broken off just below flush." If that's the case, it's very possible that you have a lot of air in your front lines, which would cause the lack of front brakes and the calipers to freeze up after sitting for long periods.

Anyway, it sounds like you got new calipers which should fix that bleed screw issue, and yes, the MC might simply be toast. Let us know where you're at when you get the new MC installed.

-Bryan

[spider2081]

I didn't see mentioned to loosen front brake lines at the master cylinder and look for fluid when the pedal is depressed.
I'm thinking the piston for the front brakes has to move for the piston for the rear brakes to move. Just a thought.

[DieselSpider]

The linings of the brake hoses can degrade and come loose inside the hoses even when the outside of the hose looks good so that they either plug the hoses completely or can behave as one way valves. As long as the braided reinforcement is intact there may be no bulges or apparent swelling visible either. If they were changed 10 years ago and potentially sat open due to broken bleeder screws then the fluid likely became full of algae and mold along with turned acidic damaging the hoses. Even if a master cylinder replacement is also needed the rubber hoses are all suspect and should also be changed and that includes the hoses between the master cylinder and the brake fluid reservoir along with those at each wheel position and the rear brake compensator valve. After replacing all the rubber hoses, etc its best to draw at least a pint of fresh brake fluid through the system using a vacuum bleeder to get as much of the algae , mold, rust, etc out of the hard lines and compensator valve without grinding it into the piston seals or compensator valve components as it would be by pumping the brake pedal. On one car the buildup was so bad I had to flush the brake system again a month later to get the residue that had loosened up in the brake system cleared out of it. Brake fluid absorbs water from the air through the brake reservoirs vented cap (none seal 100% and the ones with the float such as is common on the 124 allow for greater absorption of humidity) and it will eventually have algae and mold develop in it which makes flushing out brake systems every 2 years a critical service which too many fail to perform.

The red coating should be hi temp rubber anti-squeal which is a good thing as it also insulates the pistons a bit from absorbing as much heat from the pads. One should wait the amount of time indicated on the package to allow the anti-squeal coating to set up after its applied before installing the pads in the calipers. Higher quality pads include enough red anti-squeal coating in packets to coat the backs of all 4 pads. A good brake job includes the anti-squeal coating along with the lubrication of the guides and slides on the caliper mounts being cleaned and coated with a high temperature silicone brake grease.

Note that some of the original rubber formulations used on the Spider brake components are not fully compatible with DOT4 Brake Fluid and some of components such as hoses are still being sold that are using the old rubber formulation so use DOT3 Brake Fluid whenever possible unless you are absolutely certain that every rubber or plastic component in the brakes sealed system is now DOT4 compliant.

[Texsardo]

Thanks everyone. I went ahead and replaced the Master cylinder along with calipers, pads, hoses. Finally got it working but now I suspect vacuum canister. Brakes work well, at about 6 inches from floor but idle increase when she stops.

[manoa matt]

10 years is a lot to ask of rubber brake hoses. I tend to change the fluid every 2 years. Replace all rubber hoses, and rebuild the calipers every 4 years. The piston seal in the caliper can also swell and lock the piston in place.