Rear brake hose replacement, 1973 C10

[BRetty]

All,

I am replacing a ruptured hose on my '73 C10, and I have a few questions about the process.

My square: '73 C10, 350 smb, longbed, lowered 4.5/6, dashboard and steering column (and other parts?) from '81 Suburban, many things not done, or done poorly, or never finished, by PO.

______ THE BACKGROUND ________

My brakes went out two weeks ago. I had noticed some warning signs the day or two before: twice brake pedal was suddenly stiff with no travel, once (right before I got to work) pedal coasted down to the floor. Heading home that eve, I checked brakes in parking lot, drive-STOP!, drive-slow brake, drive-STOP!, it seemed to be holding pressure. I planned to park it at (near) home, leave it there, and take it in to mechanic on corner first day off.

HA! I got one mile and failure began, more travel on pedal, then suddenly pedal hit the floor and would not return, I rolled through a red light while frantically grabbing for the pedal with my hand. AAargh.

IMPORTANT -- My BRAKE warning light had been on since I bought the truck. It was the proportioning valve wire. I redid the electrical this summer but was so focused on electrical problems that I never considered it might be a real warning indicating prop valve was stuck in fail mode. I had not noticed brake problems but in retrospect I was getting quite a lot of brake dust on my front wheels. MIGHT BE IMPORTANT.​

Opening the hood, I had extremely low fluid. A friend gave me a ride to AutoStore for more brake fluid.

INTERESTING -- Looking in my parts manual, my master cylinder and reservior doesn't look like anything I see in there. Mostly the cover is flat, not domed, and there is no retaining clip on the top. I don't have a pic to include right now but I will...​

The seal/gasket was not sealed -- in the rear section, one corner was loose and sucked down into the well. Hmmm.

I topped the reservior up, and after a few false starts with not capping the reservior right, I had enough brake pressure to try getting home.

Brakes were OK for the few miles home, but just as I turned into my neighborhood pedal went to floor again. I engine braked and got her stopped (I have no parking brake, repairing that is a separate post). I was slammed at work (also a separate post) so when parking enforcement was due to come 'round, I paid to have her towed to work, where it is flat and I am off the street and we have blocks and jacks and buckets and tools.

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So in in daylight on flat ground, I started looking where I was noticing a leak that had just started -- I noticed it when I was towed and the two days parked at shop. Rear differential

I can crawl under the back of my truck without jacks, so I crawled in and saw this:

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The Arrow saying BUSTED! is where the hose is cracked, dripping fluid and generally defeating all hopes of pressurization. So I have ordered that hose and will replace it then move on from there I checked all the other connections and lines and didn't see any other signs of major leakage, so I hope this fixes it enough to get it in to the shop.

Some questions about the procedure:

-- The hose I ordered comes with an integral Tee-junction. I will dig out the old tee-joint from its crust of congealed brake fluid on top of the diff. Is there anything to know about removing and re-inseting the hydraulic fittings rom the old Tee into the new? I assume the lines run to the wheels are double-flare ends that will seat into the new fitting just by wrenching. ?

-- I also assume that the hard brake line to the new hose, through the bracket, is a straightforward line wrench procedure? Is the connection securing to the bracket a separate nut/fitting that is integral to one of the lines?

-- The exhaust on this truck is a hack job, and I need to replace it all before another muffler just falls off, but FOR NOW, should I worry about the connection being that close to the exhaust pipe?

-- I will need to bleed the brakes after all this. Is $50 for a HFreight vacuum bleed kit a good investment since I will be doing this myself?

-- Is removing the radiator fan and fan shroud simple enough, or are there pitfalls? I need to get better accedd to the prop valve so I can make sure things are kosher while bleeding the brakes.

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Thos are my questions for now. I appreciate any advice offered before I tackle this on Tuesday. My car buddy is Deep in the Heart of the Great State of Texas at his grandfather's 100th birthday, so his phone availabality is limited right now. GMSB is my other, other lifeline.

THanks in Advance,
BRetty

 

[fast68chevy]

unthread the two 3/16" lines from the hose end block. and unbolt the bolt holding the hose end block to the axle bracket. thats it. and as long as the exh pipe isnt hitting the line or hose then it shiould be fine. you just wont want physical contact. if there is contact then you will want to tweak the hose end frame bracket some, or move the pipe some. you wont ned a bleed kit or anything,. you will only just have some air in the very rear lines.. on the axle tubes.. easy. a few pedal pumps will push all the air out of these. very quickly easily. or even gravity bleed

or just attach asmall diameter hose from the bleeder screws into a jar with some fluid in bottom and then you can bleed by youurself a few pedal pumps.

 

[BRetty]

Thanks for the advice, @fast68chevy

The rain has stopped and my replacement hose is coming in tomorrow, so I will take the lines apart after work and hope the "replacement" hose actually has the proper fittings to mate with the existing lines.

BRetty

 

[PrairieDrifter]

The fitting coming from the frame rail has a push type clip that slides under a lip on the hose fitting, and then against the bracket, it will have to be slid out, notice the orientation of this clip, the hump should be "away" from the bracket. Would recommend loosening fitting before doing this. The hose should come with a new clip, if not reuse the old one. The proportioning valve should be accessible from the underside of the truck. Some bleeding may be required.

 

[Curt]

I say why mess with any of the old.You can do all new lines and hoses for 100-150$.Stainless,top of the line.I tried messing with my 40 year old brake lines and hoses,looked at cost to replace it all and said why am I doing this.

Hardest part of it all was bleeding the system.

 

[80BrownK10]

I say why mess with any of the old.You can do all new lines and hoses for 100-150$.Stainless,top of the line.I tried messing with my 40 year old brake lines and hoses,looked at cost to replace it all and said why am I doing this.

Hardest part of it all was bleeding the system.

If the lines aren't stuck and twist off just replacing the bad parts is what I would do as well. But who knows might be growing good money away. But if one part breaks that will then need to be done and then off to the next part.

To the OP I would loosen the lines on the differential after I cleaned it up with a pressure washer so you can see what your doing. Then unbolt the rubber from the hardline. Get it out of the bracket then unbolt from differential. Then put the new one on. Hook the rubber to the hardline and then the two hardliners to the block. I wouldn't buy a bleeder device if your not planning on much brake work in the future. That's a lot for one use. You have been given good advice about gravity and the bottle trick. If this doesn't make sense. All you do is crack the bleeders. Let fluid run out while keeping the system full. To get the last air out you can zip tie a 20oz coke bottle near the bleeder. Run a length of tight fitting hose from bleeder to bottom of the bottle. Make sure the hose is sitting under brake fluid that you have put into the coke bottle. Pump the petal 3 to 4 times watching the reservoir level so that it doesn't suck air. This pushes air out while letting it only suck fluid back in. If this doesn't make sense or your not confident in that, rent a mighty vac from auto zone or advance and suck the air out with it. It includes instructions. Or just get a buddy, wife, neighbor, neighbor kid or someone to sit in the truck for 3 minutes to pump the pedal for you.

I replaced all the rubber on my truck last year. I had no idea how old that rubber was but it had visible cracks and was leaving lots of black rubber as it was disintegrating if you touched them. I didn't want to die being pushed off a highway pulling a trailer for a failed 20-40 year old rubber hose. Spent $50 or so and replaced all the old rubber lines.

 

[Curt]

Yes sir @80BrownK10 ,not a fan of just throwing money at any situation.I have been guilty of this before.However,brakes is definitely a area that I will buy the best I can afford,replacing anything that has a hint of suspect.

Whether it’s a kid running in the street after a ball,or something else,I wanna stop.The original lines,mainly the connections was not tip top.Replaced with new lines,stainless at that.much mo better yo

 

[80BrownK10]

This is the reason I replaced all my rubber lines. Didn't want one blowing out at the wrong time.

Yes sir @80BrownK10 ,not a fan of just throwing money at any situation.I have been guilty of this before.However,brakes is definitely a area that I will buy the best I can afford,replacing anything that has a hint of suspect.

Whether it’s a kid running in the street after a ball,or something else,I wanna stop.The original lines,mainly the connections was not tip top.Replaced with new lines,stainless at that.much mo better yo