An entire brake job?

[Aviodont]

My son was driving the 83 K5 a few weeks ago and had to pull over because he said the brakes began going all the way to the floor and taking a long time to stop.

Inspection revealed that the master cylinder was empty of fluid. I didn’t notice any fluid staining of the reservoir, the lines or the booster under the cylinder. I did not check at the wheels at that point, just thinking the master went bad.

Today, I re-examined. I was unable to turn any of the line nuts at the cylinder or the 4 wheels. The rear right wheel has a shiny dried fluid at the bottom of the inside of the wheel. I can’t picture it being anything else but brake fluid that dripped down.

Attached are photos of the cylinder and the terminal end of the five lines (the truck came with a brake trailer gizmo that one of the lines goes to under the dash).

I **REALLY** don’t feel like messing with brake lines. I did that for a 69 Firebird 10 years ago, which, granted were much more cramped than the K5 would be. From the looks of the right rear brake line but and bleeder valve (actually all 3 wheels), it looks like the lines may not survive the removal.

Thoughts?

 

[ZooMad75]

Looks like the rear with wetness on the inside of the wheel had a leaky wheel cylinder.

With the reservoir low and no wetness at the calipers I’d check if the master cylinder is leaking out of the back where the pushrod is.

 

[eodcoduto]

Depending on funds, I would replace the front rubber lines and the rear rubber one. Attack the bleeder screws with rounds of pb blaster and a propane torch. That rear wheel cylinder needs replaced so don’t worry about that bleeder.

 

[CT-BLAZER]

A little heat on the front caliper near the bleeder+ a 6 point socket hammered over the bleeder should be able to remove the bleeders...

Rear is ready for new pistons, shoes + rebuilding hardware.

.Steel lines.... Order a new set 50,/50 one side will twist from corrosion

 

[Wes Harden]

Start prepping to undo those lines. Wire brush them, spray penatrent oil( WD-40 is not penatrent oil) tap the body of the wheel cylinder with a small ball peen, let sit. Do this a few times while waiting on parts. You may still need new lines. Inline tube was having a new years sale

 

[JoshHefnerX]

Long pedal gets you into trouble, brake pedal gets you out. I wouldn't play around w/ brakes and replace anything that is at all questionable.

 

[ktmoutfront]

And another trick to get the flavored brake lines to com loose is, only us quality tubing wrenches and tighten them just a tick before trying to remove them.

 

[Polymath]

Mine looked a lot like that when I first got it and started tearing into it. I already had it in mind to replace the front lines, calipers, rotors, drums, master and wheel cylinders, and all the drum guts. I was hitting it with penetrating oil twice a day for a week while all the parts were on order and I still needed breaker bars and an impact wrench to get everything apart.

 

[Blue85]

At the master cylinder, if you can't get the lines free, an option is to re-flare the factory line so it's a little shorter. Sometimes it's hard to find lines with those correct fittings anyway. So if careful work with good wrenches is not working, you can cut the line off and pound a 6-point socket on to save the fitting. Don't even try a normal box wrench for risk of rounding the corners. The wheel cylinder fittings are most likely to be rusted solid (again, cutting the line and using the socket works much better), but replacing the line across the axle tube isn't too bad of a job. It's the ones running from the Master to the proportioning valve and along the frame that are PITA.

But what reason is there to suspect there is anything wrong besides a wheel cylinder? Definitely start there and see if it's fixed. Of course, running a master cylinder dry is not good for it and may have moved some crud around to wreck a seal. Certainly a good idea to do visual inspection on all parts at all 4 corners, but every new part is also suspect these days, just like the old ones already on there.

 

[Aviodont]

... It's the ones running from the Master to the proportioning valve and along the frame that are PITA.

...

is their a difference between distribution block and proportioning valve? LMC calls this a proportioning valve

 

[dyeager535]

It's actually a combination valve, so all are wrong lol.

Proportioning iirc ONLY distributes the fluid, while the combination valve does that, plus shuts off front or rear with a failure, AND trips the brake light with a failure.

Somewhat semantics, but there is a difference. What LMC shows is correct, just wrong (but common) name.

Usually there is nothing wrong with the combination valve. It's brass. Maybe internals, they do seem quite robust though.

I'll have to re-do my lines (to include fuel), I am going to buy one of the hydraulic flaring tools however. The bending IMO is the worst part, and as mentioned, up front particularly. If all I was doing were the brake lines I'd be tempted to go with pre -bent stuff.

 

[Aviodont]

It's actually a combination valve, so all are wrong lol.

Proportioning iirc ONLY distributes the fluid, while the combination valve does that, plus shuts off front or rear with a failure, AND trips the brake light with a failure.

Somewhat semantics, but there is a difference. What LMC shows is correct, just wrong (but common) name.

Usually there is nothing wrong with the combination valve. It's brass. Maybe internals, they do seem quite robust though.

I'll have to re-do my lines (to include fuel), I am going to buy one of the hydraulic flaring tools however. The bending IMO is the worst part, and as mentioned, up front particularly. If all I was doing were the brake lines I'd be tempted to go with pre -bent stuff.

Oh, trust me, I am going pre-bent, although I am dreading snaking the lines and all the cuss words that will accompany it! I will likely change this valve if I do everything.

 

[Aviodont]

Anyone think I might be able to avoid brake line replacement by using this guy’s hack?

 

[Wes Harden]

This great after the tubing nut has broken free, but the wrench doesn't have a alot of swing and the nut won't spin with fingers.
Have done any prep work? Wire tooth brush the nut and brake pipe. Real penatrent oil, tap the wheel cylinder boss with ball peen. Good quality flare wrench. I have to say I haven't yet found any better or even equal to snap on's line wrenches. Look at eBay when shopping.

 

[tRustyK5]

Maybe I'm a hack, but I find some decent needle nose vise grips better than any line wrenches, at least for initially breaking them free. I managed to remove all the OG brake lines from my 57 Pontiac that way. Granted the lines were in fair shape, but I was not having any luck with my line wrenches. A bit of penetrant on the nut, and some finesse with the needle nose vise grips got em free every time.

 

[Wes Harden]

Have resorted to needle nose vise grips a time two. Thou as last resort.

 

[sweetk30]

20+ years in rust belt life as a pro . . .

his line in the video has rust pitting and not long for world anymore so he should have fixed that . does his trick work yes .

i just heat the nut up almost glowing red with brazing tip on my oxy/acy torch and dump cold water on it . the shock busts the rust loose good . once swapped out your going to bleed the system anyway so who cares if the fluid gets hot . but MAKE sure to run the nut back and look for pitting under the nut area on the line .

all this said tho is it worth it to not just swap out the hard line from the wheel cylinder to flex hose on axle and be 100% safe ...


and make sure the grease fittings clear the axle shafts upfront at the upper ball joints . normaly there a side joint to clear or greased and plugged with a solid fitting included in the ball joint as there is not much room to fit all in the knuckle .

 

[76zimmer]

Those m/c lines don’t look too bad, clean them well with a wire brush, and use some penetrating oil, or trans fluid/mineral spirits mixture (see youtube) and be patient by rocking the nuts back and forth just a little at a time until the nut breaks free. As mentioned use a good line wrench or solidly clamp locking plier jaws on the nut so it won’t slip.
If those are original lines throughout I would plan on replacing all the rubber lines, and the crossover on the rear axle, and both wheel cylinders. Use the same procedure to break loose the caliper bleeders too. If not get some rebuilt ones. Evaluate the other components as you get into it.

good luck!

 

[Blue85]

replacing the line across the axle tube isn't too bad of a job. It's the ones running from the Master to the proportioning valve and along the frame that are PITA.

all this said though, is it worth it to not just swap out the hard line from the wheel cylinder to flex hose on axle and be 100% safe? ...

That's what I was saying. If the fitting backs out easily and those lines don't look crusty, then luck is on your side. If not, isn't it like $8 a side to replace? In some cases, the bends could be made more gradual so you could re-flare and re-use the line after it's cut off. I think most of the auto parts stores offer loaner flare tools.

 

[Chickntrk]

Anyone think I might be able to avoid brake line replacement by using this guy’s hack?

That guy is a quack, what do you do when you get the wheel cylinder tight and it’s not lined up to bolt back in….if the line is that rusty it needs replaced. I’m surprised it didn’t break with all that horsing around he was doing. I wouldn’t want Eric the car guy working on my car.