MGB & GT Forum
brakes brakes brakes
Posted by Mike W5525
Mike W5525
Mike Wilkins
Tampa, FL, USA
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Oct 19, 2014 01:56 PM
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I'm new to the site and could really use your help! My roommate has a 1979/80 MG B that I have been working on for her. ( Replaced Fuel Pump, Radio, Master Cylinder) Just replaced front and rear pads and wheel cylinders along with all associated rubber hoses. trying to bleed the brakes, which I opened the rear and was letting gravity do the initial bleed. the passenger side rear went well. problem is the driver side rear can't get any fluid to come. even applied vacuum to that side and nothing. had her in the car pumping the brakes and nothing. just rigged an air hose from the needle valve to the front so I could pump and control the open and close and discovered that the petal is getting wet with brake fluid - now what is going on. is the master cylinder blown again? or is it something with the servo? and is there a proportioning valve in the rear? The rubber hoses that I replaced in the rear go to a "T" then steel lines run to each wheel. I feel out of place with this car. I know my way around American cars and Volkswagen ----- any info appreciated
JuancarlosMGB
Juan Perez
San Salvador, San Salvador, El Salvador
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1974 MG MGB GT "El Cherada"
1978 MG MGB Racecar "El 81 De Carrera" 1995 Honda Civic "Beasty Boy (Race Car)" 1999 BMW Z3 Coupe "BATMOBILE" |
Oct 19, 2014 02:25 PM
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Wait wait wait...So, your roomate is a girl, and she drives an MGB! You are a lucky guy
Maybe you could test your system part by part. You can test your brake pump by plugging the outlets and pumping carefully. If the pump is building up pressure without bleeding, it's ok. Then you can go further. Hold on, the guys here will help you.
Edited 1 time(s). Last edit at 2014-10-19 02:27 PM by JuancarlosMGB.
Maybe you could test your system part by part. You can test your brake pump by plugging the outlets and pumping carefully. If the pump is building up pressure without bleeding, it's ok. Then you can go further. Hold on, the guys here will help you.
Edited 1 time(s). Last edit at 2014-10-19 02:27 PM by JuancarlosMGB.
Oct 19, 2014 02:43 PM
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Check the brake line going along the top of the axle and see if it is crushed. Common occurrence.
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Mike W5525 thanked lewisrn for this post
Mike W5525
Mike Wilkins
Tampa, FL, USA
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Oct 19, 2014 03:23 PM
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Yea she's cool and she likes to work on cars some! (as long as it's not heavy). So if I close everything and try to pump the brakes up and it stays, it should be cool, even though I am nit getting any fluid? thanks JuancarlosMGB
and thanks lewisrn When I replaced the rubber I inspected the lines and they where good. is the "T" a proportioning valve or is pt a simple "T"?
and thanks lewisrn When I replaced the rubber I inspected the lines and they where good. is the "T" a proportioning valve or is pt a simple "T"?
Oct 19, 2014 03:29 PM
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With a few words in Google, you can find most anything:
http://www.mgexp.com/article/bleed-brakes.html
Roger N. Tanner
Professional Engineer, Retired
http://www.mgexp.com/article/bleed-brakes.html
Roger N. Tanner
Professional Engineer, Retired
JuancarlosMGB
Juan Perez
San Salvador, San Salvador, El Salvador
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1974 MG MGB GT "El Cherada"
1978 MG MGB Racecar "El 81 De Carrera" 1995 Honda Civic "Beasty Boy (Race Car)" 1999 BMW Z3 Coupe "BATMOBILE" |
Oct 19, 2014 03:32 PM
Joined 16 years ago
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In reply to # 2828157 by Mike W5525
So if I close everything and try to pump the brakes up and it stays, it should be cool, even though I am nit getting any fluid? thanks JuancarlosMGB
That would mean that your pump is ok, just the pump. Then you could focus on another part of the system. Maybe a brake line is clogged.
dickmoritz
Dick Moritz
Philly 'burbs, PA, USA
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Oct 19, 2014 03:54 PM
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In reply to # 2828131 by lewisrn
Check the brake line going along the top of the axle and see if it is crushed. Common occurrence.
x2
Check the steel line, not just the rubber hose. Steel line is often crushed by feeble-minded tow truck operators who throw their J-hooks over the axle...
Dick
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(Often wrong, but always certain)
Oct 19, 2014 04:13 PM
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In reply to # 2828098 by Mike W5525
discovered that the petal is getting wet with brake fluid - now what is going on. is the master cylinder blown again?
In the late model cars, it's pretty hard to get MC fluid onto the pedals as it is isolated by the booster.
Are you sure she was pumping the brake pedal and not the clutch? just checking.
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Oct 19, 2014 11:44 PM
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The tee at the rear axle is just a tee not a valve. Check the hose that goes to the tee, they will break down inside but look fine on the outside. Then they work like a check valve, fluid will only go one way. Also check the steel lines on the axle housing, they get crushed easily by jackstands.
Mike W5525
Mike Wilkins
Tampa, FL, USA
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Oct 20, 2014 05:01 AM
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Thank you all!!!! I replaced the rubber hose and checked the steel tube one of the retainers was broke but other than that it is good. I removed it from the wheel cylinder and still no fluid so now I am going to remove it all together and check it out. (the car has sat for about a year until I could get to it as I have been working out of the area.
Mick from Scotland
Mick Rae
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Oct 20, 2014 11:50 AM
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this is probably not the case, but just in case..........if youi have dual circuit brakes........I came accross this on a Midget recently, and it required the pressure warning switch to be unscrewed a bit (located inner wing, other side from master cylinder, the was a US spec car), otherwise only one side would bleed. Afraid I cannot explain better than this as it wasnt something I was familiar with, but worked through it till it was the only thing left.
Oct 20, 2014 12:57 PM
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This thing can be a problem at times. What it does is shuttle the pressure off to two rather than four wheels in the case of a line leak. If it trips, it migh still be in the closed position as it applies to two of the wheel cylinders/calipers.
Oct 20, 2014 01:16 PM
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The 79/80 would have the warning circuit but it is integral to the brake MC, screws in from the bottom. (no H-block).
It appears he is getting fluid to one rear side, not the other. Got to be in the hardline that crosses the axle. I still suspect it has been crushed somewhere.
It appears he is getting fluid to one rear side, not the other. Got to be in the hardline that crosses the axle. I still suspect it has been crushed somewhere.
Oct 20, 2014 01:38 PM
Joined 12 years ago
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X2 Clay. If he is getting fluid to one side and not the other, the problem is somewhere between the "T" and the brake cylinder. The shuttle valve is front/rear. I would suggest detaching it at both ends and applying air. Possible some kind of blockage there.
Oct 20, 2014 01:46 PM
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When I first started going thru the new to me 74 car, I discovered that the left rear brake line was all but blocked by internal corrosion. No amount of fluid would pump thru that line to the wheel cylinder. The fix was to replace it. Keep in mind that the brake lines on this car were/are steel. Steel corrodes. DOT 3/4 fluid is hydroscopic ("absorbs water". the water rusts the inside of the tubes. This is why we are advised to change the brake fluid every couple years.
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