General brake question

[tuna boy]

Looking to pump out the brakes on my Honda Pilot. Went on line and they suck the old dot 3 refill the tank open a bleeder into a bottle with dot 3 in the bottle so it cannot suck in air dand pump away with brake pedal. Stopped at the dealer and he said that you need a vacuum bleader. Claims that when you pump with the pedal the seals in the master will sometime leak afterwards because they have never had to move that far in their entire service life.
Is that true?

I did my 1100 by pumping and did not have a problem.

 

[joedrum]

hmmmm not sure sounds fishy info to me

 

[Omega Man]

What Joe said, suggesting a possible costlier repair to make a sale. :roll:

 

[dan filipi]

I can sorta see the logic behind that but never had it happen.

 

[mcgovern61]

Absolute nonsense! It is a hydraulic cylinder. It is designed for maximum movement within the reach of the cylinder and the seals should never be exposed to "excess air" or you would have bigger problems every time the shoes and pads wear down to nearly metal and the throw of the master increases! ! :smilie_happy:

 

[dan filipi]

Well the throw of the master should never increase during pad wear, the wheel cylinders are what moves to compensate for that.

 

[mcgovern61]

dan filipi » Mon Oct 13, 2014 1:04 pm[/url]":269s7ipj]
Well the throw of the master should never increase during pad wear, the wheel cylinders are what moves to compensate for that.

Agreed unless you have rear drum brakes and the adjuster are not working. The increase in the space in the wheel cylnders cause the brake pedal to move further (hence the master cylinder throw increases). Either way, you cannot exceed the length of the cylinder bore anyway.

 

[dan filipi]

mcgovern61 » Mon Oct 13, 2014 11:55 am[/url]":1ub8wi94]

dan filipi » Mon Oct 13, 2014 1:04 pm[/url]":1ub8wi94]
Well the throw of the master should never increase during pad wear, the wheel cylinders are what moves to compensate for that.

Agreed unless you have rear drum brakes and the adjuster are not working. The increase in the space in the wheel cylnders cause the brake pedal to move further (hence the master cylinder throw increases). Either way, you cannot exceed the length of the cylinder bore anyway.

True dat, it's been so long since I've dealt with those frozen rear adjusters on drum brakes that didn't work I forgot about them.
Can I hear a big hallelujah for 4 wheel disk!!

 

[mcgovern61]

Can I hear a big hallelujah for 4 wheel disk!!

YES and NO!! I have an '02 Hyundai Elantra with rear drums and finicky adjusters!! :rant: :whip:

 

[Steve83]

On an old system, there might be some corrosion on the MC bore walls that could damage a seal. The Honda manual suggests a 15mm spacer be placed between the brake lever and handlebar when bleeding the brakes to prevent excessive piston travel. I put a block of wood on the floor, under the brake pedal when bleeding car brakes. I have seen MC seals damaged by over-travel. Actually, if the system is that old, the MC should probably be rebuilt anyway.

 

[slabghost]

mcgovern61 » Mon Oct 13, 2014 2:06 pm[/url]":1ebyqxsr]

Can I hear a big hallelujah for 4 wheel disk!!

YES and NO!! I have an '02 Hyundai Elantra with rear drums and finicky adjusters!! :rant: :whip:

Many models use the parking brake to set rear adjusters. If you don't set the parking brake they never adjust.

 

[AApple]

tuna » Mon Oct 13, 2014 11:36 am[/url]":1fmvmn7u]
Claims that when you pump with the pedal the seals in the master will sometime leak afterwards because they have never had to move that far in their entire service life.

True, but sorta misleading, imo. Opening a bleeder and pumping the pedal WILL cause the piston/seals to move farther into the bore than they have "normally" been moving. If there is buildup(crap, in technical terms) in the bore, it CAN damage the seals. Not that it will, but it IS possible. I always caution folks that are foot bleeding brakes to never go all the way to the floor with the pedal with the bleeder open....1/2 pedal is enough. This is one of the reasons reman master cylinders on cars rarely ever work right....they haven't been properly bled, and the seals get damaged from over-pumping the pedal.
Bike masters don't move as much to begin with, but consider how far your car brake pedal will move in a full swing.....8-10 inches in most cases.... :shock: The piston in the cylinder will move prolly 3" when empty, but only 1/2"-1" or so when everything is working right... :whistling:

 

[mcgovern61]

Many models use the parking brake to set rear adjusters. If you don't set the parking brake they never adjust.

We use the parking brake everytime we park, but doesn't set the adjusters. I have to hit the brakes several times while backing out of the driveway to keep them adjusted.

The other car has 4 way discs!!

 

[slabghost]

mcgovern61 » Mon Oct 13, 2014 3:48 pm[/url]":3u4sp0rl]

Many models use the parking brake to set rear adjusters. If you don't set the parking brake they never adjust.

We use the parking brake everytime we park, but doesn't set the adjusters. I have to hit the brakes several times while backing out of the driveway to keep them adjusted.

The other car has 4 way discs!!

My Ranger adjusts the same way. So I pull in the drive and back out and stop hard at the end of the drive. Seems to work fine.

 

[Ansimp]

Steve83 » Tue Oct 14, 2014 5:23 am[/url]":crdahgzl]
On an old system, there might be some corrosion on the MC bore walls that could damage a seal. The Honda manual suggests a 15mm spacer be placed between the brake lever and handlebar when bleeding the brakes to prevent excessive piston travel. I put a block of wood on the floor, under the brake pedal when bleeding car brakes. I have seen MC seals damaged by over-travel. Actually, if the system is that old, the MC should probably be rebuilt anyway.

+1 :yes: :good:

 

[charles franz]

+2 Mustang uses the E-brake for adjusting the pads.

 

[AApple]

A wee bit :0fftopic: , but, the self adjusters work differently on different car brands. Generally, if the adjuster is at the top of the drum(under the wheel cylinder), it adjusts by using the parking brake(in reverse). If the adjuster is at the bottom of the shoes, it works by using the brake pedal in reverse. On my 'Burban, the self adjuster will ONLY work using the park brake in reverse. I put it in reverse, back up, and stop the truck with the park brake. Do that several times, and you can feel the service pedal get higher, indicating the shoes have adjusted some. These results are not typical....your results may vary....please consult your physician before starting any new braking regimen....

sorry...got off track there....now back to your regularly scheduled discussion on master cylinders.... :mrgreen:

 

[joedrum]

thats great apple

 

[Ansimp]

+1 :good:

 

[charles franz]

Apple, I did not mean to be a wiseguy, I was trying to be helpful to those folks that may have a problem with adjusting they disc brakes, I did NOT mean to offend anyone with their knowledge.