79 El Camino brake issue pedal goes way down

JP

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#1
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MAKE: Chevy
MODEL: El Camino
YEAR: 1979
MILES:
ENGINE:
DESCRIBE ISSUE....

I'm selling my parent's 1979 El Camino and don't have much history on it, although I've driven it a couple of times. The brake pedal goes nearly to the floorboards and the brakes seem to be working.

A guy came to look at it yesterday and guessed that a brake line had rusted through, although I've not seen any evidence of leaking brake fluid.

I'm aware it could be a matter of proper adjustment of the rear brakes, but I'm not interested at this point in fixing it, just selling it.

My question: if a brake line were leaking, wouldn't the fluid level in the master cylinder be down and wouldn't that be a quick way of determining whether or not there was a leak in the brake lines or calipers/brake cylinders?
 

tdark

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My question: if a brake line were leaking, wouldn't the fluid level in the master cylinder be down. Yes

wouldn't that be a quick way of determining whether or not there was a leak in the brake lines or calipers/brake cylinders? Sure would be :)

Adjust the rear brakes. Your pedal should be better. No fluid loss then no leak. Raise wheels off the ground and see if all four brakes are working
 
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#4
First, words of caution...Applying the parking brake on an old car can cause problems you don't want. So, unless you are sure that the p-brake will properly release when you want it to...do not apply it.

If the pedal is low due to a drum brake adjustment problem, the pedal will probably feel better when the p-brake is applied and worse when the p-brake is released.

Another indicator of adjustment needed would be that pumping the pedal quickly two or three times gives you a much better pedal.
 

JP

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Well...the forward master cylinder reservoir is empty, the back one full.

#%@&*!

So could be anywhere from the master cylinder to the calipers or brake cylinders, right?

Does the forward vs. rear reservoir help localize it to the front or rear brakes? I'm not sure if there is a proportioner.
 

JP

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Anyone have a brake line diagram for a 1979 El Camino?
 
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#7
I would add fluid and start pumping the pedal. If there is a ruptured line, after maybe 30-50 pumps, the pedal will begin to stiffen, there may be a farting noise under the car, and then fluid will begin to drip. Wild card would be leaking wheel cylinder, inspect for damp appearance at one of the backing plates.
If it helps...if the front rez cavity is smaller than the rear, that usually means that the rear brakes are the problem area.
 
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jd

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I don't have a manual or diagram. That said the gOOgle Images indicate that the Front Chamber (away from the Firewall) is the REAR brakes. Back in "The Day" the Master Cylinders were a casting, and one Chamber (the Rear one, nearest to Firewall) was much larger. It supplied the Front Calipers since they require more fluid than rear drums.

So, I'd be looking for a failed flex hose (chassis to center of rear axle), a rusted steel line as you mentioned, or a failed wheel cylinder. I'd sooner believe it's a hose or steel line. Rear Cylinders leak with more of a seeping, but if that El-C has been standing, more probable the little pistons in there are stuck and the rear brakes won't even work.

Hint on Steel Lines: You probably can't buy an exact replacement that's correct with both lengths and bends. Unless you're REALLY good, and have bending tools, get a line that's Much Too Long and form Coils in it. Or maybe Loops. Then you gain some flexibility in reaching your connections.
 

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If it's a substantial leak, it would squirt out under pressure vs. a "seeping" small leak, right?

I'm assuming there's some air in the brake line, regardless of where the leak is, or at least will be when I add fluid and pump the pedal. Is there any chance I might hear the air or fluid bubbling out without having to take off the wheels?

Long story, it's not stored at my garage and I'm a little hesitant to drive it with the brakes only partially operational. I'd have to haul a jack and tools over to where I'm storing it.

Would dye help locate the leak if it's a "seeping leak"? Again, my hope is that I can find it without pulling off the rear wheels and drums...but I guess a brake cylinder is easier to replace than a brake line.

So am I correct in that there's a steel line from the MC to the rear, then a flex line between the steel line and the proportioner, then a steel line from the proportioner to each of the rear brake cylinders? The flex line is reinforced rubber?
 
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billr

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#12
I urge you to drive this to your place so you can work on it conveniently and without rush. Wait until 5-6 AM on Sunday morning, you may not encounter a single other vehicle to contend with on the road.
 

JP

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I urge you to drive this to your place so you can work on it conveniently and without rush. Wait until 5-6 AM on Sunday morning, you may not encounter a single other vehicle to contend with on the road.
Yeah, that's my concern... It's a very short drive with two lights in between where it's stored and the freeway, but still. One need for a panic stop and it's off to the junkyard.
 
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#14
Pinching a rusty brake line blowout with vice grips to "get it home" has been done before. Pretty safe if it is a rear line. Carry plenty of fluid, add more to rez as soon as the warning light comes on.
 

jd

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#15
Pinching a rusty brake line blowout with vice grips to "get it home" has been done before.
Tricks like this are priceless. THANKS!!!
This'd work on a blown rubber hose too, if it wasn't failed right at the source. Repaired a bus with no brakes on the left front. Had two single wheel cylinders, each fed by its own hose. They went through a standoff bracket that looked good, but rust had formed in the clamping area of the bracket and shut both hoses off.