swampedout Posted November 26, 2020 Share Posted November 26, 2020 Ive been dealing with brake issues since I bought the truck (we have had our 1 year anniversary recently, celebrated by me given the dmv money to renew the registration:nabble_smiley_thinking:) Basically, I have a really soft pedal and over time I lose brake fluid going to the rear. Brake light comes on, I refill the MC, bleed the rear and the light goes off. Ive already replaced the MC and booster. Ive looked under the truck but dont see any obvious leaks. Im planning on replacing all the brake lines with copper nickle line next month if I cant track it down before then. I will probably also do new pads and rotors up front while Im at it, although the pads have plenty of material on them. Also, the parking brake cable is disconnected so no Ebrake whatsoever. Link to comment Share on other sites More sharing options...
Machspeed Posted November 26, 2020 Share Posted November 26, 2020 That's really strange. I would have thought you might have a leaking wheel cylinder. With all that you've done, certainly you've inspected those. Maybe leaking at the proportioning valve. Gary and Jim will be on this quick, I'm sure. Keep us posted. Link to comment Share on other sites More sharing options...
old55pete Posted November 26, 2020 Share Posted November 26, 2020 I was gonna say to just pop off the rear wheels and drums. Then I saw that you have a 3/4 ton and that aint so easy as a 1/2 ton because of the full floating axles. Is there fluid coming out from between the backing plate and the drum on the rear? There is a rear brake hose that feeds both rear brakes, it is normaly on the rearend housing on the left side between the left rear spring and the diff housing, is it wet? have some one push the brake pedal real hard and see if it is leaking or balooning up under pressure. As for putting copper tubing in to replace steel brake lines, I dont know about that. I dont think it can handle the pressure. I am gonna leave that one alone as someone may have done it and it is still working without a falure Link to comment Share on other sites More sharing options...
85lebaront2 Posted November 26, 2020 Share Posted November 26, 2020 I was gonna say to just pop off the rear wheels and drums. Then I saw that you have a 3/4 ton and that aint so easy as a 1/2 ton because of the full floating axles. Is there fluid coming out from between the backing plate and the drum on the rear? There is a rear brake hose that feeds both rear brakes, it is normaly on the rearend housing on the left side between the left rear spring and the diff housing, is it wet? have some one push the brake pedal real hard and see if it is leaking or balooning up under pressure. As for putting copper tubing in to replace steel brake lines, I dont know about that. I dont think it can handle the pressure. I am gonna leave that one alone as someone may have done it and it is still working without a falure Look at the junction of the left side rail and the crossmember in front of the rear fuel tank. It is a low area and collects water and dirt I lost my rear brakes towing our 5th wheel to Gloucester County VA, this meant no brake controller either. Try to find brake fittings and lines in the boonies on a weekend. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 26, 2020 Share Posted November 26, 2020 The others have covered it pretty well. But the brake shoes will soak up some fluid, although if your leak is enough to require filling the master again then I doubt it is that. As was said, pulling the drums might be difficult, so check out the other things first. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted November 26, 2020 Share Posted November 26, 2020 I was gonna say to just pop off the rear wheels and drums. Then I saw that you have a 3/4 ton and that aint so easy as a 1/2 ton because of the full floating axles. Is there fluid coming out from between the backing plate and the drum on the rear? There is a rear brake hose that feeds both rear brakes, it is normaly on the rearend housing on the left side between the left rear spring and the diff housing, is it wet? have some one push the brake pedal real hard and see if it is leaking or balooning up under pressure. As for putting copper tubing in to replace steel brake lines, I dont know about that. I dont think it can handle the pressure. I am gonna leave that one alone as someone may have done it and it is still working without a falure By '86 all these heavier trucks had the Sterling 10.25" axle. Edit: Steve, I must have scrolled down to your post that I was replying to and seen "'86". D'oh! No problem popping the drums off and no left hand threads either! Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted November 26, 2020 Share Posted November 26, 2020 Sam, I got a copper/nickel brake line kit from Amazon. Had a bunch of fittings too. I'll link it when I check my purchase history. The fluid is going somewhere. I'd check where Bill said, at the hose* junction in the corner of crossmember and frame rail. Does your truck have one of those load level proportioning valves with an arm attached to the rear axle? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted November 26, 2020 Share Posted November 26, 2020 Sam, I got a copper/nickel brake line kit from Amazon. Had a bunch of fittings too. I'll link it when I check my purchase history. The fluid is going somewhere. I'd check where Bill said, at the hose* junction in the corner of crossmember and frame rail. Does your truck have one of those load level proportioning valves with an arm attached to the rear axle? Sam, this is the kit I bought: https://www.amazon.com/dp/B07W2Z8F5X/ref=cm_sw_r_cp_apa_fabc_uecWFb8Q1RRNJ?_encoding=UTF8&psc=1 25' is plenty of line from MC to rear hose, and both sides of the axle. I have some left over but I'm not sure if it would be enough to complete the front. I'm also going to suggest that you need to adjust your rear brakes. Without any emergency brake it's not likely they'll adjust themselves. That should take a lot of travel and softness out of your pedal. Link to comment Share on other sites More sharing options...
85lebaront2 Posted November 27, 2020 Share Posted November 27, 2020 By '86 all these heavier trucks had the Sterling 10.25" axle. Edit: Steve, I must have scrolled down to your post that I was replying to and seen "'86". D'oh! No problem popping the drums off and no left hand threads either! Jim, he has a 1984, so will have the Dana 60 which uses the integral hub and drum. On Copper for brake lines, not a good idea, it gets brittle with age and if it is soft enough to bend, it is soft enough to expand un der the high pressures used. Link to comment Share on other sites More sharing options...
Frank Wyatt Posted November 27, 2020 Share Posted November 27, 2020 Jim, he has a 1984, so will have the Dana 60 which uses the integral hub and drum. On Copper for brake lines, not a good idea, it gets brittle with age and if it is soft enough to bend, it is soft enough to expand un der the high pressures used. Check the rear drum backing plates for wetness as that would be a sure sign of a leak, either brake fluid from the wheel cylinders or the axle seals. We all know the axle grease has a unmistakable smell and is easy to distinguish the two from each other. Link to comment Share on other sites More sharing options...
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