Need help troubleshooting brakes

[1929Chrysler]

Three years ago I had the entire brake system rebuilt on my '29 Chrysler. This included the master cylinder and wheel cylinders all re-sleeved and new cups installed. Also have new brake lines and pads all the way around. The car has less than 500 miles since the rebuild and when it was new the pedal felt perfect. Late last year I noticed the pedal had to travel a lot farther for the car to stop. This week I notice the pedal goes all the way to the floor and I feel no resitance. I obviously can't drive like this.

I checked all the flare connections and I don't see any obvious leaks. Please help me with this as I am not entirely familiar with this braking system. It does have a brake can resevoir that is mounted to the fire wall and it appears that brake fluid would gravity feed down to the master cylinder when needed?? Is this how the system works? Yes, there is brake fluid in the resevoir.

Thank you very much for your help.

Dan

[keiser31]

Adjust then bleed the brakes.

[hwellens]

If you have no leaks your master cylinder is bad or somehow you got a lot of air in the system. If the master cylinder full, the fluid is getting past the cups without putting pressure on the wheel cyliders. Try bleeding the brakes.

[Guest abh3usn]

Sometimes the brake hoses fail internally. It's quite common in British cars. The rubber colapses internally and pinches off the brake fluid to the wheel cylinder. You wouldn't see a leak as the fluid is not flowing to the wheel cylinder. There could also be debri built up in the brake lines which may have come loose recently. Remember with traditional brake fluid (Non-synthetic) the water in the fluid settles at the low points of the system which causes corrosion.

[Guest Plymouthy]

actually a master cylinder will get cruded up on a lightly used vehicle faster than on a car that is driven a lot...

if your reservoir is still full, pedal is light or none..but you can eventually pump them I would guess internal bypass of the master...oft times a simple teardown amd clean and reassembly will get them going again. This is a temp fix only to verify condition. You can get the pedal back up by pump and bleed and when there..do this test...let set..if pedal is still firm...apply very light pressure..if it holds but after a bit it then starts slowly decending to the floor..she be by-passing..hit it harder and it stops..seals are expanmding under pressure and applying said pressure to the wheel cylinders..I would recommend a new kit in the master if this is the case..your seals are conditioned to a rest position due to lack of use or very premature wear..or not correct tolerance on the re-sleeve.

[1929Chrysler]

Quick update: I was getting no pressure to the wheel cylinders so I removed the main brake line coming out of the master cylinder and installed a bolt in it's place to peform a test. With the bolt in place I pressed the pedal and there was no resistence, so it appears the problem is with the seals in the MC. Any ideas where to get new seals?? Remember, it has already been re-sleeved.

Yes, I am using DOT 5 silicone brake fluid.

Dan

[Guest clare30]

Just been through similiar experience with one of our cars. Had problems with leaking master cylinder on our 29 dodge. We use silicone fluid in our cars. The rubbers in the master cylinder had distorted caused by reacting with the silicone fluid. Rebuild the master cyl but use rubbers compatable with silicone (including the valve). Our other 29 dodge has had no problems. If your master cylinder has a inch and a quarter bore we used a kit for a Ford F250 part# K4X. Hope this helps. Regards Clare.