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Brake issue

Jan Accord

Jan Accord

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Messages
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Location
Slovenia
Car
Honda Accord CN1
Hi guys [emoji2]

Today i was street racing with some guy and i had to push the brakes few times in extreme situation but something strange happened.
During braking the pedal started to drop, alomst to the floor but the brake effect did not drop the first time. The second braking after that happened the brake effect was way lower and the pedal too.
After a race i tryed with the car parked and the engine running, to pust the pedal hard and it drops almost to touch the floor.
With the engine off so no "brake booster" after one or two pumps the pedal is hard like rock and from the top when i push it realy hard it drops maybe one or two centimeters, so almost nothing.
The brake system is almost new ( check my brake thread ):
New brake master cylinder
New braided brakes lines
New discs drilled and slotted
New brake pads
New ABS sensors
New brake fluid ( yes is bleeded properly )

I had a similar symptom when i had the EBC RedStuff pads but after i changed them i didn't noticed that anymore until now.

To be honest i'm a bit afraid to drive it because i don't know what to expect even if i tryed the brakes again and the car stops but the pedal is not where it should be.
This brake system was already checked by two differend Honda services and both confirmed the perfect shape of it.
The MOT passed without problems

I realy don't know what could cause this problem so i really need your support.

Already made a little research and i found that the brake proportioning valve could cause this kind of sympromps... Opinion??

What do you suggest?

Thanks in advance
 
What pads and discs are you running?

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This sounds like a brake fluid issue.
Has your fluid dropped if not might be worth bleeding the brakes.
 
Mtec discs with Ate pads.
The brake fluid is almost new and the level is at MAX mark.
 
What brand master cylinder and hoses? There is pressure loss in system it could be master cylinder or braided hose

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Tryed two different master cylinders.
Bosch OEM and Metelli. With both the same story.
The hoses are HEL
 
There is a test will check

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Sorry am at work the test is honda accord brake booster and master cylinder testing look on honda-tech and perform test

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I would start by bleeding the entire system again. Also look at what the fluid level is doing when someone operates and lets go of the brake.

That pedal motion is making fluid go somewhere that isn't the brake calipers.

If your brake fluid is new and clean you can catch it and reuse it.
 
The whole day i'm searching where could be trapped an bubble of air because the system was gravity bleeded, preasure bleeded, vacum bleeded and two person bleeded.
We have put over the brake system like min. 5 liters of oil but i think that there is an point where could be trapped.
I will try to bleed as first the master cylinder.

http://cloud.tapatalk.com/s/58c5e4d0d13dd/MasterBleed.gif

As you can see above is an example where could be trapped an bubble of air if not bleeded properly after after the system was fully discharged like in my case.
Our Accord's are the perfect example do do this trick when the master cylinder is replaced and not bleeded BEFORE is mounted.
Thats because the cylinder is attached with a certain angle to the brake booster and the fluid ports are lateral so logicaly there is no way to bleed it properly when mounted because the output ports are in the center of the cyrcle so there be always a little part in the camber.

The easyeat way to do this is with the help of some master cylinder bleed kit like this:
http://cloud.tapatalk.com/s/58c5e82ef1db2/13911-007.jpg?

With the cylinder in the hand you can easily push the air in the direction you want with different movements and once the air is out of the camber the job is done

http://cloud.tapatalk.com/s/58c5e8a4398ac/613.31.jpg?

Hope this will help
 
Used to get this on the Jaguar mk 3, Police model, when driving hard the fluid used to boil and braking was non existent, after cooling down they were fine again.

The cure is DO NOT RACE on public roads, save it for the track, because all of you will be going the same way. LOL
 
edgeoftime said:
Used to get this on the Jaguar mk 3, Police model, when driving hard the fluid used to boil and braking was non existent, after cooling down they were fine again.

The cure is DO NOT RACE on public roads, save it for the track, because all of you will be going the same way. LOL
Click to expand...
The OP lives in Slovenia. From what I saw of Croatia when I was there 10 years ago, the public roads are already laid out like rice-tracks LOL
 
Regarding the OP's questions, the BEST way to tackle this is to jack up the car at the rear in the middle as soon as you've done some heavy braking e.g. drive along a road in Slovenia and come to a Slovenian stop, jump out with a trolley-jack, and jack it up under the rear towing bracket. Once the car is up in the air, check to see which of the two wheels are easy to rotate by hand. Have an ***istance apply braking pressure and see if the wheel rotates when the brake-pedal is released.

In my experience, the best way to test and/or do any work on the rear brakes on these cars, is to jack up the car at the rear under the towing bracket. It's actually easier as well.

btw chock the front wheels
 
edgeoftime said:
Used to get this on the Jaguar mk 3, Police model, when driving hard the fluid used to boil and braking was non existent, after cooling down they were fine again.

The cure is DO NOT RACE on public roads, save it for the track, because all of you will be going the same way. LOL
Click to expand...
I know that it's not the smartest thing to do this on the roads, but is interesting that the person which advise you to not race is explaining you how he boiled the brake fluid with hard driving.

However you're right about street racing but this is not the solution i'm searching for.

Thanks anyway [emoji6]
 
Jan Accord said:
I know that it's not the smartest thing to do this on the roads, but is interesting that the person which advise you to not race is explaining you how he boiled the brake fluid with hard driving.
However you're right about street racing but this is not the solution i'm searching for.
Thanks anyway [emoji6]
Click to expand...
I got the impression that edgeoftime wasn't racing as such, more part of an occupation.
 
Channel Hopper said:
I got the impression that edgeoftime wasn't racing as such, more part of an occupation.
Click to expand...
John Hamer has probably occupied many people and places, but I don't think he was ever involved in an occupation of Slovenia :lol:
 
freddofrog said:
Regarding the OP's questions, the BEST way to tackle this is to jack up the car at the rear in the middle as soon as you've done some heavy braking e.g. drive along a road in Slovenia and come to a Slovenian stop, jump out with a trolley-jack, and jack it up under the rear towing bracket. Once the car is up in the air, check to see which of the two wheels are easy to rotate by hand. Have an ***istance apply braking pressure and see if the wheel rotates when the brake-pedal is released.

In my experience, the best way to test and/or do any work on the rear brakes on these cars, is to jack up the car at the rear under the towing bracket. It's actually easier as well.

btw chock the front wheels

Or put your hands on the wheels, and also take a deep breath this will tell you two things the smell of burning pads and the pain as it shoots into your hand.
Click to expand...
 
Use dot 5.1 brake fluid

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The boiling point is much higher

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