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Sat Jun 13, 2015 4:04 am

What are the recorded and proven facts of incidents of brake failure due to a blockage in a brake line?

Sat Jun 13, 2015 4:58 am

another overkill scenario.

Blow the lines out with a blow gun, run some brake fluid through them, fasten the lines up, and load the system up with brake fluid.

If the lines are totally skanky--replace them with new.

Done.

Your Head must hurt at the end of the day Dave from overthinking everything you're touching--
This is another unnecessary procedure.
Forget about it.

Sat Jun 13, 2015 5:35 am

Terry Kay wrote: another overkill scenario.

Blow the lines out with a blow gun, run some brake fluid through them, fasten the lines up, and load the system up with brake fluid.

If the lines are totally skanky--replace them with new.

Done.

Your Head must hurt at the end of the day Dave from overthinking everything you're touching--
This is another unnecessary procedure.
Forget about it.

With the alarming rate of new cylinder failure, I think it is irresponsible to NOT clean out the lines removing potential problem causing bits.

Over thinking? ....... No.

Many options presented? .... Yes

Again, not in this to turn a profit with billable hours. More interested in once and done.

To leave it be or to only marginally clean things is Not unlike installing a rebuilt automatic transmission and not flushing out the oil cooler and lines.

Dave

Sat Jun 13, 2015 6:35 am

Dave,

Since way prior to serving my GM apprenticeship, when I was just screwing around in the driveway as a kid, or at Cadillac, then Chevrolet, and later on at my own shop, I have never seen any good reason ( nor has anyone else for that matter ) to flush, clean, scrub, or sanitize the interior of any brake lines, or hydraulic lines.
They are bad rusted, cracked broken?
Change them.
Bleed the system, and that's all, that's it.

And I'm not only talking about automobiles, I'm talking about any heavy equipment included.

Flush all of the hydraulic lines on a D-9?
D-8--you gotta be kidding me--
Remove & replace the bad lines, & re-fill, your all done.

How bout a lift cylinder, pump, lines on a straight dump truck or 30 ft dump trailer?
No way.
No flush required-- and these vehicle mentioned above are in one heck of a rougher service arena's, & operate at higher hydraulic pressures than your Vans brakes or clutch.

Your taking a trip into a place that is beyond overkill.
If the lines are all rusted out on the exterior, look questionable, change them.

I feel your talking yourself into an easier path than doing what should be done in making a 100% positive repair by assuming you can clean out the inside of some fuzzy looking hydraulic lines and all will be good.

The low road repair system.
But this is where your mindset is--
" I fix rather than replace" as just quoted from another post on resealing engine water jacket seals.

There are sometimes , and in certain area's of interest where "fixing" just ain't the way to ride Dave--forget the frugal path.
It'll lead to more poorly repaired issues.
But then you'll say--"fix it once "
Not in this area you aren't.

Furthermore, you posted all kinds of possible solvents and looked for replies on what to use.
Who in the heck could ever answer that question?
Nobody.
Because no one in my lifetime or anyone else's for that matter has ever performed such a wacky process.

Get the questionable hydraulic lines outa the van & replace them.

No cleaning needed--load up with hydraulic fluid & go.

"Fix it once" Dave--

Sat Jun 13, 2015 9:01 am

Steve M,

Yeah, that's what I was thinking as well. The brake system is an extremely simple thing. I've heard a people claim the inside of brake lines can break down and cause a blockage in the line that keeps the caliper from retracting. I've heard claims that crud can block a brake line. Rubbish. When you press on the brake, the PSI is such that few people could engineer a blocked line by intentionally fitting something in there that would hold up to the pressure - much less a random something accomplishing it. As the guy from Princess Bride would say "Inconceivable!!" Heh...

Introducing solvents into a brake system using people's random input from the internet is a fundamentally unsound idea. Flow some fresh brake fluid in there and let 'er rip!!

Sat Jun 13, 2015 9:20 am

Darius,

The Only Things That "I've Heard" folks ever say, or seen myself of decaid,delaminate in any braking system, Steve, Ron, Bill, or Sam, Pete, George, or Ida, is rusted, holed through steel line or rubber union hoses at the back side of the brake cylinder's.

The steel lines unless totally junk, never require cleaning, vacuuming, or flushing, Vladimir.

Sat Jun 13, 2015 12:03 pm

Steve M. wrote: What are the recorded and proven facts of incidents of brake failure due to a blockage in a brake line?

what makes you think crashes are investigated to the same degree as deaths from blood vessel blockage?

his van also lives in vast sea of salt so the exterior of the lines need to be inspected carefully - might as well replace them

do what you want - just don't do it near me

Sat Jun 13, 2015 12:28 pm

I have replace a bunch of front rubber lines on 97-04 F150's that have caused uneven pad wear. Its the darndest thing, trucks brake like shit, passenger pads are brand new, drivers side are shot. New rubber hoses and bleeding and they stop like new. I wouldn't say it if me and others hadn't experienced the exact same thing.

If the rubber or metal lines are at all questionable replace the damn things. Especially the rubber hoses... Unless you know they are new or less than 5 years old just replace them.

Sat Jun 13, 2015 12:44 pm

All I really want to do is flush this crap out of the lines BEFORE I install my new rubber bits and rebuilt cylinders. I don't want them leaking due to an easily preventable problem.
It looks like mosquito larvae in the brake fluid! ......

I figured if there was a good product to use to remove any buildup while I flushed the lines...... Why not?

I will be using chemicals and flushing crap out of the Evaporator..... Why not the Brake lines? It only makes logical sense.
The same people telling me to flush one system with harsh chemicals tells me not to do another system in a like manner...... :roll:

Sleep easy folks......
IF the metal brake lines show any sign of rust or rot they will be replaced.
And......
All..... I mean ALL rubber bits will be new.

I get the rust concerns for sure! I grew up in Jersey....... My Type 1's lines are usually rusted away, any GM product has rusty brake lines develop in no time flat!

I've replaced way more than my quota of rusted lines over the years..... Brake AND fuel.

Dave

Sat Jun 13, 2015 1:44 pm

I change my fluid per schedule which includes a flush, change pads, shoes, hoses, Proportioning Valve, Master Cylinder and rusted metal lines as necessary for safe functioning of the system.
Is it a bad idea to run a "cleaning" fluid through the system?
It cannot hurt.
Is it necessary?
Show me what comes out after running 2-3 flushes that exchanges the amount of fluid in the system with each flush and there is the answer.
(more than 2 flushes is probably over-kill.)

The qualifying question is whether or not you have been the owner from when the car was new or it's been sitting in neglect for x number of years and then you should replace all components except the brake lines if the exterior of each line is clean - if you have a doubt change it.

I'm not braking in fear every time I step on the pedal if I maintain my system.

Sat Jun 13, 2015 1:46 pm

The only chemical that has been recommended by me to flush out the ac lines is air dryer winter alcohol.
Stop.

From that pretty sound & direct guote, I' ve seen mineral spirys, grain alcohol, lacquer thinner derivitives written in.

So other tha alcohol for the ac you've not seen me mention anything else np other solvents.

For the brakes I suggeted the alcohol again becase it isn't a harsh solvent.
It evaps quick.
But whencI cam back to my senses, change the chocolate Maypo spitting lines.

They are junk & probably cause you more problems down the road.

But you know better than this--- didn't even have to ask.

Sat Jun 13, 2015 1:53 pm

This Van is a 1986.
It has only 108,000 miles, owned by owner two since 1990.

It has sat Unused by owner two since 2002? I've had it for almost three years ....... motionless.

Lightly used but long neglected.
It's use as a Summer vacation unit spared it the severe text book Rust Belt rust issues.... It is Only gently rusted! :lol:

Going through it setting things right.

First order of business is to clean it.....
Then decide on renewal or reuse based upon an examination after the cleaning is done.

That's why I want to clean it.
What cleaning agent to use?

Clean will reveal rot.....
But.....
Oily soil prevents rust too!

Dave

Sat Jun 13, 2015 2:19 pm

When I worked at BMW, the flush interval was to do it every 4 years. When people wait 5+ tears, it will get muddy like the pics you posted. That's normal.

We would just remove the master cylinder reservoir by pulling it off the master cyl itself (not removing the master cyl). Wash it in the parts washer to get the crud out & make sure the float switch still works or is not broken. Rinse it out really well & use shop air to dry it.

Reinstall it onto the master cyl flange, fill with fresh bmw brake fluid, top off the pressure bleeder with brake fluid & pressurize it.

When you first crack open the bleeder, it looks like mud or coffee when it first comes out. Sometimes, I would lightly tap on the caliper to get it to flow good.

Once it looked clean, move onto the next wheel.

A pressure bleeder works really well to flush out the crud.

Note, the only time I replaced lines is when they rusted from the outside in, never inside out

Dont use any fancy brake fluid

Good luck

Sat Jun 13, 2015 2:31 pm

I plan on Using DOT 4 as indicated on the Reservoir.

Anyway......
I figured........
"What's the harm?"

Three cups.....

Cup 1
After gravity draining the RF Wheel, I shot a gentle blast of compressed air through. This is Brake Fluid only...... No solvent.

Cup 2
Using aerosol Brake Cleaner I shot a long blast of cleaner into the pipe followed by a gentle puff of compressed air.

Cup 3
Again using Brake Cleaner followed by a puff of air

Is that rust in the cup or dirty brake fluid residue?
I'll let it evaporate, wrap a magnet in a piece of plastic wrap.... See if it is ferrous or not.

Common sense says......Had I not flushed the metal lines, my new brake fluid would immediately look like cup 2

Dave

Sat Jun 13, 2015 2:42 pm

That looks like old brake fluid.

I've never had any luck with gravity bleeding. Some guys swear by it tho.

IMO, get a pressure bleeder & bleed a couple of cans thru every spring. It's really easy.

Sat Jun 13, 2015 3:06 pm

tjet wrote: That looks like old brake fluid.

I've never had any luck with gravity bleeding. Some guys swear by it tho.

IMO, get a pressure bleeder & bleed a couple of cans thru every spring. It's really easy.

Remember. Its just metal pipes right now. No master cylinder, wheel cylinders or calipers installed.
Remnants of the old flex hoses are still fastened, I just cut them as I removed components.

Dave

Sat Jun 13, 2015 6:41 pm

Mentioned only once, but important: do not use DOT 5 in a DOT 4 system. Completely different animal, and you probably not like the results.

There, I said it.
Mark

Sat Jun 13, 2015 9:56 pm

Those lines have plenty of carp in them, and I'd be afraid the the old moisture laden fluid has performed pretty good in eating the inside of the lines & hardware, spitting out this much Ovaltine--

I wouldn't screw around with this at all.
Get new lines & brake hardware in this van prior you finding out in a real inopportune moment that in fact they a junk when you happen to stand of the hooks in a desperate stopping move--

Sun Jun 14, 2015 12:50 am

IdahoDoug wrote: Steve M,

Yeah, that's what I was thinking as well. The brake system is an extremely simple thing. I've heard a people claim the inside of brake lines can break down and cause a blockage in the line that keeps the caliper from retracting. I've heard claims that crud can block a brake line. Rubbish. When you press on the brake, the PSI is such that few people could engineer a blocked line by intentionally fitting something in there that would hold up to the pressure - much less a random something accomplishing it. As the guy from Princess Bride would say "Inconceivable!!" Heh...

Introducing solvents into a brake system using people's random input from the internet is a fundamentally unsound idea. Flow some fresh brake fluid in there and let 'er rip!!

actually it is not rubbish..... the hoses do become restrictive and do prevent the brakes from retracting after the brake pedal is released. the symptom is dragging brakes and if ignored that may over heat the brake and ruin the caliper rubber parts.
I have personally found this out on more than one car that I purchased used. The problem is not when the brakes are applied, cause the pressures are great and hence the fluid can force its way thru the blocked hose. After the pedal is released, the only pressure for the fluid to flow back out of the wheel cylinder is that of the springs on the shoes or worse still the flexibility of the rubber seals on the caliper pistons. it is not a lot of force at all.

So yes hoses can act as one way valves and that is a fact not rubbish.

Sun Jun 14, 2015 12:52 am

djkeev wrote: I plan on Using DOT 4 as indicated on the Reservoir.

Anyway......
I figured........
"What's the harm?"

Three cups.....

Cup 1
After gravity draining the RF Wheel, I shot a gentle blast of compressed air through. This is Brake Fluid only...... No solvent.

Cup 2
Using aerosol Brake Cleaner I shot a long blast of cleaner into the pipe followed by a gentle puff of compressed air.

Cup 3
Again using Brake Cleaner followed by a puff of air

Is that rust in the cup or dirty brake fluid residue?
I'll let it evaporate, wrap a magnet in a piece of plastic wrap.... See if it is ferrous or not.

Common sense says......Had I not flushed the metal lines, my new brake fluid would immediately look like cup 2

Dave

the fluid don't need to evaporate, just runt eh magnet under the paper cup.

that don't look like a lot of rust to me. (if it is rust) See if more comes out,