MGB & GT Forum
Please remind me - Brake Bleeding Question
Posted by mgcyclo
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Aug 20, 2014 10:44 AM
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Aug 20, 2014 10:50 AM
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Tradition would say 'start with farthest'.
I've never heard a good explanation for why that is, other than all our dad's told us to do it that way.
Documenting my project in my journal at https://www.mgexp.com/home#journal
I've never heard a good explanation for why that is, other than all our dad's told us to do it that way.
Documenting my project in my journal at https://www.mgexp.com/home#journal
Aug 20, 2014 10:50 AM
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29desoto
M Wayne Sanders
Otis, OR, USA
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1965 MG MGB V6 Conversion "Carmine"
1973 MG MGB GT "Eliza - FIRST PLACE - MG2013" 1984 Chevrolet Corvette "The Green Weenie" 1994 Chevrolet S10 "Lil Red" |
Aug 20, 2014 10:50 AM
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Tim -
Start at the furthest away and work towards the MC.
Wayne Sanders
Rose Lodge, OR
(TD 4288)
"I don't care to belong to any club that accepts people like me"-joined Willamette Valley Club in 2011
79/65 MGB - Carmine- V-6 - T-5
This car is now very nearly completely done. Sure to find something else, but not now.........And 12 years later, I'm starting to fix things that were new when we built the car. It's pretty well de-bugged!
Start at the furthest away and work towards the MC.
Wayne Sanders
Rose Lodge, OR
(TD 4288)
"I don't care to belong to any club that accepts people like me"-joined Willamette Valley Club in 2011
79/65 MGB - Carmine- V-6 - T-5
This car is now very nearly completely done. Sure to find something else, but not now.........And 12 years later, I'm starting to fix things that were new when we built the car. It's pretty well de-bugged!
29desoto
M Wayne Sanders
Otis, OR, USA
Sign in to contact
1965 MG MGB V6 Conversion "Carmine"
1973 MG MGB GT "Eliza - FIRST PLACE - MG2013" 1984 Chevrolet Corvette "The Green Weenie" 1994 Chevrolet S10 "Lil Red" |
Aug 20, 2014 10:52 AM
Top Contributor
Joined 13 years ago
13,098 Posts
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Steve types faster than I do!
I heard the reason for starting furthest away is that if you start closer, you may "contaminate" the closer lines with air while bleeding the further ones. Kind of made sense to me.
Wayne Sanders
Rose Lodge, OR
(TD 4288)
"I don't care to belong to any club that accepts people like me"-joined Willamette Valley Club in 2011
79/65 MGB - Carmine- V-6 - T-5
This car is now very nearly completely done. Sure to find something else, but not now.........And 12 years later, I'm starting to fix things that were new when we built the car. It's pretty well de-bugged!
I heard the reason for starting furthest away is that if you start closer, you may "contaminate" the closer lines with air while bleeding the further ones. Kind of made sense to me.
Wayne Sanders
Rose Lodge, OR
(TD 4288)
"I don't care to belong to any club that accepts people like me"-joined Willamette Valley Club in 2011
79/65 MGB - Carmine- V-6 - T-5
This car is now very nearly completely done. Sure to find something else, but not now.........And 12 years later, I'm starting to fix things that were new when we built the car. It's pretty well de-bugged!
Aug 20, 2014 11:41 AM
Joined 9 years ago
242 Posts
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Here's one explanation:
"The longest "run" to a wheel cylinder is going to have the lowest pressure due to having the most surface area due to the length of the tubing run. Usually, this "low pressure" is going to cause the air to migrate in that direction. It's like electricity taking the path of least resistance in a circuit."
"The longest "run" to a wheel cylinder is going to have the lowest pressure due to having the most surface area due to the length of the tubing run. Usually, this "low pressure" is going to cause the air to migrate in that direction. It's like electricity taking the path of least resistance in a circuit."
Topic Creator (OP)
Aug 20, 2014 11:56 AM
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Aug 20, 2014 11:58 AM
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In reply to # 2774478 by 29desoto
Steve types faster than I do!
I heard the reason for starting furthest away is that if you start closer, you may "contaminate" the closer lines with air while bleeding the further ones. Kind of made sense to me.
I heard the reason for starting furthest away is that if you start closer, you may "contaminate" the closer lines with air while bleeding the further ones. Kind of made sense to me.
Another similar reason:
"The reason behind bleeding farthest to nearest is because if there is air in the rear brake lines and you bleed the front first it will draw that air back into the brake lines. You'll get the air out of the front since the lines to the front brakes are short, but the lines to the rear of the car are quite long, so the air just gets stuck in the middle.
If you are like most you bleed the brake several times before going to the next brake, thus drawing the air well into the brake system.
There is a chance you might not ever get a nice firm pedal. The air would just keep going back and forth but never out."
Aug 20, 2014 12:09 PM
Joined 16 years ago
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Topic Creator (OP)
Aug 20, 2014 12:34 PM
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Joined 15 years ago
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Hi Drake,
I figured someone would ask that.
It's a long story, I'll try to summarize.
1) It leaked as they all do and was properly plugged a long, long tme ago.
2) Because of that it always bothered me that it was there.
3) Along comes a V-8 conversion along with a Ford rear,
4) Brake balance goes all out whack
5) Decide to install a proprtioning valve to help rectify balance
6) Bye bye junction box
7) Brakes balance still way off
8) Researsh shows incorrectly sized rear brake cylinders
9) Work with a very patient / understanding counter guy at my local Napa store to source the correct size brake cylinders
10) Brake balance restored, junction box long gone.
Not, bad. About ten years history in 10 bullet points :-)
I figured someone would ask that.
It's a long story, I'll try to summarize.
1) It leaked as they all do and was properly plugged a long, long tme ago.
2) Because of that it always bothered me that it was there.
3) Along comes a V-8 conversion along with a Ford rear,
4) Brake balance goes all out whack
5) Decide to install a proprtioning valve to help rectify balance
6) Bye bye junction box
7) Brakes balance still way off
8) Researsh shows incorrectly sized rear brake cylinders
9) Work with a very patient / understanding counter guy at my local Napa store to source the correct size brake cylinders
10) Brake balance restored, junction box long gone.
Not, bad. About ten years history in 10 bullet points :-)
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