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Brake pedal goes to floor after changing master cylinder

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  #1  
Old 09-04-2007 | 11:48 AM
Hondapt
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Default Brake pedal goes to floor after changing master cylinder

I have a 2001 Honda Accord, 4cyl, 4 door, 5 speed MT with Disc Brakes in front and Drum brakes in the rear. It had a problem with the brake pedal slowlygoing to floor.This problem still occurred after bleeding the brakes. Since there were no leaks in the brake system ( caliper, wheel cyl., lines etc)and the master cylinder reservoir remained full I replaced it with a Master Cylinder from one of the long time national auto part store brands. I benchbled the master cylinder, installed it as instructed and the bled brake system following the wheel order for that model. The problem did not go away so checked the brake hoses for wear andthey were in good condition. I also checked and adjusted the rear brake shoes. There are stillno leaks in the system and the brake fluid reservior is full. Any suggestions to correct this problem will be appreciated.
 
  #2  
Old 09-04-2007 | 12:02 PM
TexasHonda's Avatar
Super Moderator : And A Texan
Joined: Feb 2007
Posts: 9,652
From: Katy, TX
Default RE: Brake pedal goes to floor after changing master cylinder

I would suspect the master cylinder-vacuum booster pushrod offset is too large and you're not pushing the master cylinder piston at all. There is a special tool required to adjust this gap. You might try looking at the old MC and estimating how much adjustment is necessary (under dash adjustment to brake pedal linkage to vacuum booster). Note, if you overcompensate and get adjustment too tight, the brakes will lock up completely! Most MC installation instructions cover this adjustment. If you have a Accord shop manual, it has this adjustment described, although a special tool is required. If you don't have a manual, download the 94-97 Accord manual from hondahookup.com. That's better than nothing.

good luck
 
  #3  
Old 09-10-2007 | 10:15 PM
Hondapt
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Default RE: Brake pedal goes to floor after changing master cylinder

The push rod adjustment took care of my problem. I over shot the adjustment on my first try however my brakes didn't start staying on all the time until 15 minutes into my test drive. Luckly I wasn't far from home. It took several tries since it it difficult to feel how much you actually turn the push rod adjustment screw.I am a large person so getting in under thebreak pedal area was a challenge. I adapted some wrenches per the http://www.tegger.com/hondafaq/maste...djustment.htmlwebsite. I modified some inexpensive combination wrenches that I purchased at Walmart.I didn't want to ruin my good ones.

Thanks. My daughter who uses the car at college appreciates it.
 
  #4  
Old 09-11-2007 | 08:55 AM
00AccordLX5spd's Avatar
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Joined: Jan 2007
Posts: 4,322
From: Brandon, MS
Default RE: Brake pedal goes to floor after changing master cylinder

Thanks for posting the solution and that link. I know some may find it helpful. I changed the master cylinder on my '95 a few weeks ago, but I didn't run into this problem.
 
  #5  
Old 09-11-2007 | 08:00 PM
TexasHonda's Avatar
Super Moderator : And A Texan
Joined: Feb 2007
Posts: 9,652
From: Katy, TX
Default RE: Brake pedal goes to floor after changing master cylinder

Great followup post! A job like this will test the patience of anyone.

I bought an OEM master cylinder to avoid this issue. I looked at the old and new parts and they looked identical (pushrod to MC gap) and worked w/o adjustment. I didn't know what a good decision I made until I saw what was required to adjust the pushrod. Not clear to me why the designer didn't put the adjustment on the end of the pushrod at the booster. this would have made adjustment very easy.

Regards
 
  #6  
Old 09-11-2007 | 08:30 PM
deserthonda's Avatar
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Joined: Dec 2005
Posts: 4,754
From: In The Desert ( Sahara ? )
Default RE: Brake pedal goes to floor after changing master cylinder

a lot of non-honda CHEAP brake masters need to have the push rod adjusted ,, after dozen and dozens and dozen of replacement the 2 that i have never hot to adjust it are :
Honda factory
Adler brand which is OEM .
and these are also the ones that seem to last the longest ..
 
  #7  
Old 09-12-2007 | 08:49 AM
00AccordLX5spd's Avatar
Registered User
Joined: Jan 2007
Posts: 4,322
From: Brandon, MS
Default RE: Brake pedal goes to floor after changing master cylinder

I used Honda OEM. Bought it from Majestic Honda. It was at my front door within 5 days and cheaper than the dealers in town! Including shipping!
I wanted to go ahead & spend the extra $ for OEM since I already knew for a fact that I was not going to want to have to do that job a 2nd time! Bleeding the brakes really sucks if all you have is basic hand tools and a floor jack...and it is 100 degrees outside with about 90% humidity!
 
  #8  
Old 09-14-2007 | 09:26 PM
TheWays
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Default RE: Brake pedal goes to floor after changing master cylinder

get a Mityvac! if you have small spoked wheels, you don't even hafta jack up the car! bled my brakes with just a bleeder wrench and mityvac in less than half an hour, best 22 bucks I ever spent
 
  #9  
Old 09-15-2007 | 10:46 AM
sir_nasty's Avatar
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Joined: Feb 2006
Posts: 6,290
From: Montana
Default RE: Brake pedal goes to floor after changing master cylinder

I'll be.... it's less than $30.00 for that fricken brake bleeding tool.... I'm half tempted to buy one just in case....

http://www.tool-home.com/products/ca...oducts_id=5216
 
  #10  
Old 09-17-2007 | 11:48 AM
00AccordLX5spd's Avatar
Registered User
Joined: Jan 2007
Posts: 4,322
From: Brandon, MS
Default RE: Brake pedal goes to floor after changing master cylinder

I still gotta remove my wheels anyway, or at least jack up the car and try to access the bleeder without removing the wheel. IMO that would be more of a PITA than removing the wheel anyway. The spokes on the 95 are large and there is definitely not enough space between them do do it without jacking up the car or removing the wheel. The 2000 is ridin on steelies with the stock hubcaps [sm=pimp.gif]so there's no way I'm accessing those bleeders without removing the wheels. The good thing about the 2000 is, drum brakes in rear so only have to bleed the front two.
My wife is my bleeder tool. If I am working on her car, that means she is home. Therefore she can get her butt outside and mash down the brake pedal when I tell her to!
 


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