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My Brakes Went Out


So I drive a 1975 chevy stepside 1/2 ton 2 wheel drive.

My brakes are gone but I got the brakes themselves redone the summer before last.I think its the master cylinder because the fluid is full but I have no brake pressure.The pedal goes to the floor and the truck doesnt slow down.

Also my boss told me that the wheel cylinder in the back could be out and if it was there would be fluid on the inside of the wheel but there isnt any.The brakes worked fine last week and gradually i could feel the pressure going away and the pedal going down further.

Any insight on this would be muchly appreciated.


Is it really worth the trouble and time of trying to figure this out yourself??? Take it to a shop, use your saved time to train and fuck.


Thats great advice why didnt I think of that.


I have no idea if you are being sarcastic or not, but either way you're welcome, cuz it's the best answer you're gonna get.


Hey vonstinkle the rest of the guys on here will understand when I say I wasnt asking 09


Have you tried bleeding your brakes? Could just be air.

EDIT: Ehh didn't read your whole post, check your lines could be a cut?


Im gonna bleed the lines tomorow and replace the master cylinder.


before you go out and buy a master cylinder try bleeding the brakes. go to the drivers front wheel and bleed from there if nothing is coming out then its the master if you have fluid coming out with decent pressure then you might have a hole somewhere else.


He says his system hasn't lost a considerable amount of fluid, so not its not a leak. Do you still have drums on it, or have you ever upgraded to disk?


Do not take it to a shop...at least until you've exhausted every option.

I recently went to a garage to get my front rotors and pads replaced, and they told me my front calipers were seized up to the point of not functioning at all and would absolutely need replacing. Along with some other things that "absolutely need[ed] to be done to ensure safe operation of the vehicle," I was looking at a $1700 bill.

I instead bought my own rotors and pads and attempted to change them myself. While changing them, I checked out the calipers, and I was able to manually depress all of the pistons...hardly seized at all.

All in all, I saved over $1400, and it brakes fantastically.


I would ask if you have original brake lines?


Im not sure if the lines are original i want to say they are.

So here is the story again.I lost all pressure and braking wednesday and when I got home I checked the fluid and primary was almost empty so I filled it up.Then thursday morning I tried to drive it and had pressure for a second then lost it again but still have lots of fluid.But thats not to say there isnt a leak since I only tried driving it once since filling it up and for a very short distance.


That right there would be the sign of a leak somewhere and when it was so low air was able to make it into the lines. Not sure on the older body trucks but the new Chevy's like to leak around the frame just under the Box sometimes they will get really bad on the back axle but that would depend on what type of weather area you live in NY is really tough so every truck I see at the shop has signs of rust and corrosion on the brake lines

I really hope that if its a 75 that they are not the original lines the lines on trucks now don't last more then 5-6 years with out having a leak.

Auto Zone Advanced and everyone else sees brake line in rolls they now have the plastic coated lines that should hold up longer. Buy the rolls not the stright length and go from there if you find the spot that is leaking from I would say just replace them all front to back.


Here's what you have to do. Look under the master at the firewall under the hood to see if it has leaked there, do the same from under the dash inside, only if you have manual brakes. Power brakes with the booster won't leak inside the cab. Then look at all the brake hoses, lines and the back of each wheel. Your truck has disc brakes, everything from 1973 up should be equipped with discs.

Your master leakage may have been gradual and fluid can evaporate over time by a bad master cover gasket. The drop in fluid in the largest reservoir in the master is caused by front brake pad wear, the caliper pistons extend out and the fluid level drops.

Since the master is old, replace it. Get a new one, clamp it in a bench vise. Fill it with fluid. Hold 2 fingers over the line ports, use a screw driver and actuate the master with the cover off. You'll see bubbles, when the bubbles stop, the master is bled.

Install it and bleed the brakes, start with the RR, the LR, RF and LF. Do it with the engine off, even if you have power brakes.

Good luck!



If the truck was undercoated from the factory, the lines might be ok, when they start to go, the domino theory comes in. One pops, you fix it, pressure is greater and another one pops and so on.

I'd advise against using the rolled line unless you have great double-flaring skills. Most parts stores sell lines with the fittings installed in 10" increments up to 60". I use these a lot and are the best thing for driveway fixits.

If the line is a little too long, route the bends a with a bigger radius, avoid loops since they can trap air especially higher up in the system. If you have to do a loop, keep it horizontal. Longer sections can be joined with a union. Don't let the lines chafe on anything that moves, they will rub through in time.



I used to use the straight lines until I switched to the current dealership I am at now. I always hated putting on the unions while going down the line just does not see right to me when you are doing it.

But you are right if you don't have a flair tool and have not done it a few times might not be a good idea


Great info Beachguy498, thanks.


Not a problem. I used to do brake work day in day out for years until I got fed up on it and got out of the business. I used to get problems like yours almost on a weekly basis. It would come down to a bad master (leaky or bypassing internally, no leak), a blown wheel cylinder or a bad line. Try to get under the truck at night with a flash light, for some reason leaks show up better that way.

Lines tend to go bad where they chafe on axle or frame clips or lay on the frame, which collects dirt, the dirt collects moisture. An odd place to look at is where the front line runs along the crossmember.



It is the master.Also the back brakes are completly worn out.


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