Okay to Clamp Brake Lines?

Mike_04GolfTDI · Jul 18, 2019

Like the title says, is it okay to clamp brake lines shut while changing a caliper?

The instructions that came with the caliper say to do it, but I’m a little wary of doing that.

Prairieview · Jul 18, 2019

I've never been remotely comfy with the idea. Most "local" shops will do crap like that.

You need new brake fluid in there anyway.

I would only do it in an emergency.

Graham Line · Jul 18, 2019

Shop once clamped a brake line on my 4x4 while doing something. I forget what. Dove to one side under braking on the way home and I got a nice small adjustable wrench out of the deal. Never went back to the shop. They also had other issues.
But clamping the line isn't nearly as big an issue as forgetting to unclamp it.

ToxicDoc · Jul 18, 2019

Mike_04GolfTDI said:
Like the title says, is it okay to clamp brake lines shut while changing a caliper?

The instructions that came with the caliper say to do it, but I’m a little wary of doing that.

You're not supposed to hang the caliper as it stresses the hose wall unnecessarily. I can't see how clamping would not be even worse.

I used to submerge the hose end into a small glass jar (like the size of a baby food jar) half-filled with new brake fluid and keep the jar a little higher than the hard section of brake line. This creates a hydraulic seal that worked for me very well.

Now I use this:

https://www.ecstuning.com/b-schwaben-parts/8-piece-fluid-line-stopper-kit/005939sch01a/

Nero Morg · Jul 19, 2019

I have before. Just don't leave it on there long, like overnight, or forget to take it off.

PakProtector · Jul 19, 2019

Shutting off the reservoir from leaking out an open brake line is easy: Depress the brake pedal enough to start developing pressure in the calipers.

No need to go all the way to the floor.
cheers,
Douglas

RallySport · Jul 19, 2019

Yes you should be fine. I use brake hose clamps on all the cars I change brakes on UNLESS it's a really old car and the brake hoses are briddle.

I wouldn't recommend using pliers to clamp the hoses(go for it if you want) but their are actual clamp tools they make specifically for pinching brake hoses. I would think that using pliers to pinch the hoses may damage the hose.

RallySport · Jul 19, 2019

Prairieview said:
I've never been remotely comfy with the idea. Most "local" shops will do crap like that.
You need new brake fluid in there anyway.
I would only do it in an emergency.

Have you ever used brake hose pinchers? Actual brake hose pinchers? Not vise grips.? Or pliers.?

Vince Waldon · Jul 19, 2019

Yup, there's an inexpensive tool designed to do this exact thing and it does it safely and well... at least in my experience.

The guidance against letting the calipers dangle by the hoses makes sense to me, in the context of not mechanically stressing the hoses where they are crimped into the fittings. The hoses themselves are built to withstand hundreds of bars of pressure and are in my mind not overly fragile... at least not until they age and deteriorate.

gmenounos · Jul 19, 2019

PakProtector said:
Shutting off the reservoir from leaking out an open brake line is easy: Depress the brake pedal enough to start developing pressure in the calipers.

No need to go all the way to the floor.
cheers,
Douglas

I've seen that advice mentioned before. It seems like that would cause even more fluid to be pushed out of the open line. Any idea why it works?

KLXD · Jul 19, 2019

The pistons are past the ports in the master so there's no path for fluid from the reservoir to the hose. Surface tension should keep the hose from dripping, maybe. Granted it will leak the pressure that's built up. Opening the bleeder will vent this into a bottle to avoid a mess. Of course you have to find something to hold the pedal down.

If the hose is so brittle one is afraid to clamp it it's time for a new hose. Granted the outer hose has very little to do with the pressure carrying capacity of a hose but still...

Only problem I see with Vice Grips is one can damage the hose if common sense is not applied also.

I use golf tees to plug the holes in situations like this.

BobnOH · Jul 19, 2019

I clamp them with needle nose vice grips fitted with thick rubber hose. They do sell a tool for that.

Mongler98 · Jul 19, 2019

WTH???
no seriously what is wrong with these mechanics.
all you need is some foam earplugs. jam it into the banjo, never leaks again. its not holding back anything other than gravity!
never clamp a brake line, especially old rubber ones. even with a special tool. Trying to over complicate things is never a good idea. If you dont have a banjo fitting, just hold the ear plug against the brake line flare end with some electrical tape!

Mike_04GolfTDI · Jul 19, 2019

I'm replacing the copper washers on the banjo bolt, so in the time it takes to cut the old ones off (they get stuck) a lot of fluid will probably leak out before I could stuff an earplug in the banjo fitting.

I guess I shouldn't risk damaging the hoses. I do have VCDS, a power bleeder, and a couple liters of fluid on hand. I'll just let it leak and then go through the whole ABS purge routine after. It adds a bit of extra work, but if I damage a hose I'll be doing it anyway, and more.

Normally I wouldn't have even considered it, but since the instructions that came with the calipers say to clamp the lines, I was thinking I could save some time.

Mongler98 · Jul 19, 2019

So one trick is to fill the res FULL with fluid. it will run out less and ensure no air comes in, it does not drip out that fast.

mjydrafter · Jul 19, 2019

My mityvac has some little plugs that came with it. They are fairly tiny and will plug even a tiny little line. They still drip, but I just toss a rag under.

Even running out, if you're fast and have everything preset, you won't lose much fluid.

I don't clamp brake lines.

AndyBees · Jul 19, 2019

I would never clamp a brake hose ...

I always prepare for the mess in a number of ways. And, as Mongler98 indicated, I use something to plug the hose, even if it is a piece of paper towel or clean piece of rag. Yes, it ill probably drip... just make sure the reservoir doesn't get too low. Also, when you are ready to re-install the brake hose, you can let it "drain" (keep an eye on the reservoir) to remove any air as well as that procedure will flush the hard line and hose.

Also, I support the caliper with a wire made for the purpose, usually a piece cut and shaped from a coat hanger... works fine!

jimbote · Jul 20, 2019

PakProtector said:
Shutting off the reservoir from leaking out an open brake line is easy: Depress the brake pedal enough to start developing pressure in the calipers.

No need to go all the way to the floor.
cheers,
Douglas

best idea on here, and it works because the piston blocks fluid path from reservoir to line via the fluid return ports ... clamping brake lines is bad mojo and just because someone makes a tool doesn't make it cool ... think about a brake line as a timing belt, the fiber wrapping and it's bond to the rubber substrate is where it gets it's strength and when you stress this bond beyond it's "thermoset" you can break the fibers free from the substrate and create a weak point @ the crimp

Mike_04GolfTDI · Jul 20, 2019

Incidentally, the reason I’m doing this is because I went to bleed my brakes and the rear bleed screws were really tight. I managed to get one to move enough that fluid started coming out, but then couldn’t close it. It might have started to break.

I said “to heck with this” and bought two new calipers. I put some copper anti-seize on the new bleeders so this won’t happen again. I used it sparingly and didn’t get any near the tip. Just a light skim on the threaded portion.

My old calipers are probably still good, so if I can free up the bleeders I might keep them as spares or whatever. I’d rather do that with them off the car.

Mongler98 · Jul 20, 2019

Mike_04GolfTDI said:
copper anti-seize on the new bleeders so this won’t happen again.

that will actually make it worse next time you go to turn them. its not that the metals are reacting or you need lube. its just rusting in place because either your dust boots are bye bye for miles and miles or you got cheap parts. you can get stainless or coated bleeder screws.
the trick here is the put some SILICONE grease on the threads after you have it a few turns in, not to lube the threads but to keep water out, also helps in bleeding with a vac bleeder.
that crap everyone uses to solve problems just gets hard over time and heat.

SILICONE GREASE, you will thank me later, this stuff lasts and well, its just epic how good this is at keeping water off things and making sure my brake parts dont go fubar from heat and age (sliding pins and what not)

Mike_04GolfTDI · Jul 21, 2019

After having a look at the brake lines, no way would I clamp them. They are very stiff material and I’m sure it would damage them.

I just let the fluid drain and then did a full flush and ABS bleed. Brakes feel different, but they work. I guess that’s to be expected with new calipers.

Mongler98 · Jul 21, 2019

I really never understood why anyone just gets a new or reman calipers.
It is very simple to replace the seals, boots, and bleeder screws. you can 320 grit your pistons to a new shine.
The only time its even worth it is from wear down on the saddle where the pads rest but if a caliper has shims there then its never an issue. For a $8 fix per side and about 1 hour of work if you paint them vs 20 minutes and a few hundred bucks???

One of the decent break modifications is braided hoses, you will get a stiffer feel vs the old rubber that does expand as you increase breaking PSI. this is the time to change them and they are CHEAP, lets put it this way, if i trust my life on a streetbike at 150mph on some $12 aftermarket braided lines, they will be fine for a VW at 80mph!!!!

PakProtector · Jul 21, 2019

The OE lines are done with Kevlar fiber if the multiple analysis on the forum is right. There is also no shortage of folks who have reported no difference. What the bike manufacturers use is( or used to be ) more elastic than the braided lines...IDK what they use now.

On the car at 80 vs the bike at 150, the kinetic energy is not so different than you might think...

cheers,
Douglas

Mike_04GolfTDI · Jul 21, 2019

Mongler98 said:
I really never understood why anyone just gets a new or reman calipers.
It is very simple to replace the seals, boots, and bleeder screws. you can 320 grit your pistons to a new shine.
The only time its even worth it is from wear down on the saddle where the pads rest but if a caliper has shims there then its never an issue. For a $8 fix per side and about 1 hour of work if you paint them vs 20 minutes and a few hundred bucks???

One of the decent break modifications is braided hoses, you will get a stiffer feel vs the old rubber that does expand as you increase breaking PSI. this is the time to change them and they are CHEAP, lets put it this way, if i trust my life on a streetbike at 150mph on some $12 aftermarket braided lines, they will be fine for a VW at 80mph!!!!

I do it for the enjoyment of receiving a box of things from idparts.

KLXD · Jul 21, 2019

PakProtector said:
The OE lines are done with Kevlar fiber if the multiple analysis on the forum is right. There is also no shortage of folks who have reported no difference. What the bike manufacturers use is( or used to be ) more elastic than the braided lines...IDK what they use now.

On the car at 80 vs the bike at 150, the kinetic energy is not so different than you might think...
cheers,
Douglas

Pay for fancy stainless lines and they feel better. Never mind that the teflon liner has to expand some before it makes full contact with the braid or that the stock lines are rated for higher pressure.

Mongler98 · Jul 21, 2019

PakProtector said:
The OE lines are done with Kevlar fiber if the multiple analysis on the forum is right. There is also no shortage of folks who have reported no difference. What the bike manufacturers use is( or used to be ) more elastic than the braided lines...IDK what they use now.

On the car at 80 vs the bike at 150, the kinetic energy is not so different than you might think...
cheers,
Douglas

Oh no doubt, stock lines are fine, my point was that if they are dry rotted and have issues, cheap vs expensive braided lines are fine and virtually no difference.
Oh i could stop about 10x as fast as you can on a bike at any speeds but the difference is that if you hit a tree or skid out, your probably walking away from that with your life , but me, NOPE, life or death when it comes to brakes vs in a car.

Powder Hound · Jul 21, 2019

The last time I replaced a caliper, I loosened the bleeder while working the brake line. That kept the fluid flowing into the caliper instead of dripping and allowing the air inside the new caliper to bubble up into the brake system (i.e. the ABS pump). Then refill the reservoir while filling the new caliper, and everything went well.

Cheers,

PH

PakProtector · Jul 25, 2019

Mongler98 said:
Oh no doubt, stock lines are fine, my point was that if they are dry rotted and have issues, cheap vs expensive braided lines are fine and virtually no difference.
Oh i could stop about 10x as fast as you can on a bike at any speeds but the difference is that if you hit a tree or skid out, your probably walking away from that with your life , but me, NOPE, life or death when it comes to brakes vs in a car.

Don't lecture me on doing silly stuff on a bike, in addition to having put lots and lots of miles on several, I also have a World Record speeding ticket from one...as well as a World Record small fine to go with it...

112 mph over the limit.
cheers,
Douglas

Mongler98 · Jul 25, 2019

Oh lord! this isn't a shlong measuring contest dude!

KrashDH · Jul 30, 2019

Mongler98 said:
WTH???
no seriously what is wrong with these mechanics.
all you need is some foam earplugs. jam it into the banjo, never leaks again. its not holding back anything other than gravity!
never clamp a brake line, especially old rubber ones. even with a special tool. Trying to over complicate things is never a good idea. If you dont have a banjo fitting, just hold the ear plug against the brake line flare end with some electrical tape!

The earplug trick works great.

Mike_04GolfTDI said:
I'm replacing the copper washers on the banjo bolt, so in the time it takes to cut the old ones off (they get stuck) a lot of fluid will probably leak out before I could stuff an earplug in the banjo fitting.

I guess I shouldn't risk damaging the hoses. I do have VCDS, a power bleeder, and a couple liters of fluid on hand. I'll just let it leak and then go through the whole ABS purge routine after. It adds a bit of extra work, but if I damage a hose I'll be doing it anyway, and more.

Normally I wouldn't have even considered it, but since the instructions that came with the calipers say to clamp the lines, I was thinking I could save some time.

I just did all all 4 brakes around, pads and rotors, as well I had to re-build the front passenger side caliper that was frozen (new kit with seal, boot, and piston).

The trick that worked great for me was a pen that has the rubber grip on it (think the more cushy ones, not the cheap BIC ones). It was slightly larger than the banjo bore so when I shoved it in there it sealed the line perfectly. Worked great.

Okay to Clamp Brake Lines?

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