Brake pedal poor (upgrade & dot 5.1)

[Jon_G]

I'm not convinced that braided brake hoses will fix this problem. The brake feel improving when the brakes are reapplied (as described in post #1) is a classic indicator of air in the system. I suggest that the Honda dealer did not follow the correct order and procedure.

 

[burbleboy]

Before you do that, what is the mileage of the car, has it had a hard life (major MOT work or repairs following an accident) and lastly how will you feel if after fitting the braided stuff you still don't like the pedal travel ?

Are you sure there is nothing you've overlooked ?

My car has 83k on the clock and hasnt been in accident or MOT failures. Most things in my car modified and car in fantastic condition outside and underneath.

If i fit the braided pipes and pedal still the same then i wont be bothered! As i said mate, very poor pedal was only after heavy braking from 100+ to 20mph in short space of time. Done it before in civic and it pedal held up ok. Hence my concerns.

 

[burbleboy]

I'm not convinced that braided brake hoses will fix this problem. The brake feel improving when the brakes are reapplied (as described in post #1) is a classic indicator of air in the system. I suggest that the Honda dealer did not follow the correct order and procedure.

Yeah mate, defo harder pedal when pump once under braking. I will get Honda to fit braided hoses and bleed again. Once i describe my issue, Honda tech should bleed it properly/fully.

Hopefully!

 

[freddofrog]

Can anyone confirm that Nissin ABS/VSA unit is compatible with diesel model?

It wouldn't fit as a direct replacement in the diesel because the units are in a different place on each car , but if it did turn out to be due to the ATE unit being a piece of junk, the it might be an option. You'd have to make quite a few mods to get it in, and you might have to get a servo from a petrol as well. Then there'd be the question of whether the Bosch ECM would recognise the Nissin ABS unit.

 

[Jon_G]

It wouldn't fit as a direct replacement in the diesel because the units are in a different place on each car , but if it did turn out to be due to the ATE unit being a piece of junk, the it might be an option. You'd have to make quite a few mods to get it in, and you might have to get a servo from a petrol as well. Then there'd be the question of whether the Bosch ECM would recognise the Nissin ABS unit.

What would be the point?

 

[freddofrog]

What would be the point?

"if it did turn out to be due to the ATE unit being a piece of junk"

 

[Jon_G]

"if it did turn out to be due to the ATE unit being a piece of junk"

In which case either get a replacement or have the original refurbished. To embark upon a process of modifying the vehicle to take an alien VSA controller with no idea about whether it would ever work would be an odd alternative. The ATE units are not that unreliable.

 

[freddofrog]

In which case either get a replacement or have the original refurbished. To embark upon a process of modifying the vehicle to take an alien VSA controller with no idea about whether it would ever work would be an odd alternative. The ATE units are not that unreliable.

I'd slipped into Jon_G triteness mode LOL
my bad, I'll try not to do it again

Since triteness in English can be ambiguous, "if it did turn out to be due to the ATE unit being a piece of junk" was actually meant to read as follows.

"Since we're not finding anyone with a CN1/2 who can report that the braking is good when driven hard and braking hard, then, it could well be that the ATE units aren't up to it." i.e. it was a generic statement.

Note that people who upgrade their discs/pads/hoses on CL9/CM2 don't report same issues as reported in this thread, thus it is possible that if someone wants to get excellent hard braking on a CN1/2 then they might need to consider changing out the ATE ABS to Nissin ABS. Note also that the ATE ABS generally tended to give more issues on the 7th gen diesel anyway. Just an idea to bear in mind, it may be that there is no other solution to upgrading on CN1/2.

 

[Jon_G]

Ah. So more reports of diesel Accord problems must mean that diesel Accords (and their component systems) must therefore be less reliable than petrol Accords?

I don't see why this thread has become a discussion about VSA/ABS systems. The evidence presented suggests that the bleeding process was inadequate.

Until recently my brake pedal was rock solid. As I'd expect.

 

[freddofrog]

Ah. So more reports of diesel Accord problems must mean that diesel Accords (and their component systems) must therefore be less reliable than petrol Accords?

I don't see why this thread has become a discussion about VSA/ABS systems. The evidence presented suggests that the bleeding process was inadequate.

Until recently my brake pedal was rock solid. As I'd expect.

well you haven't been following what Jan Accord has been saying in this thread

neither have you been following what you yourself have said

After replacing my rear discs and pads the brake pedal has become a bit spongey... don't see how this let air into the system but I've vac bled the rears anyway. Didn't help. When stationary with the engine running, pushing the brake pedal reasonably hard results in it eventually sinking to the floor after about 30 seconds. Pumping doesn't alter the feel. No leaks, no losses.

It's only become a discussion about VSA/ABS units because you don't seem to have taken in the fact that an entire braking system includes the servo, the ABS unit, the fluid, the hoses, the calipers, the pads, and the discs

the thread has mentioned the last 5 in the chain Jon, so don't block the possibility of the first 2 in the chain

 

[Jon_G]

Slightly unfair, I did say that my brake pedal was rock solid until recently (a clear reference to my current concern, which began only when new pads were fitted).

 

[freddofrog]

Slightly unfair, I did say that my brake pedal was rock solid until recently (a clear reference to my current concern, which began only when new pads were fitted).

I know, just using standard guerilla tactics as you do LOL

 

[Jan Accord]

Guys.
This thread is going to the point of the problem.
As already mentioned few of us have the same problem and i tryed to solve it in all possible ways and even started to inventing something new to bleed but we are not talking about air in the system.
I bleeded the system from top to bottom with preassure and at the bottom vaccum, from bottom to top injecting the oil trough the nipple ,with HDS,standard vaccum bleed, master cylinder bleed, ABS/VSA bleed and bleed the proportioning valve changed the discs, pads, hoses, and master cylinder.
From each brake caliper came out at least 5 liters of brake fluid!!
I did not the servo because it has absolutly nothing to do with the sofe brake pedal.
The only thing i did not changed is that modulator and if you ask me this is where we should search and act

 

[freddofrog]

The only thing i did not changed is that modulator and if you ask me this is where we should search and act

It would be a huge mod though, I wouldn't start without thoroughly investigating the difficulties.

 

[Jon_G]

I'm not saying the OP's problem isn't in the ABS modulator/controller, just that the description of the problem suggests that air is trapped. Removing trapped air from this unit might be the issue, which could require a particular technique, not simply flushing through a large volume of fluid?

 

[Rom]

I'm new here, so can't offer much accord specific advice. But I've been a tech for 15+ years, done brake swaps on my own stuff, tracked my stuff etc.

It's quite normal for a pedal to seep down when the engine is running. The servo will vent vacuum. It shouldn't seep when the cars off. As that's purely hydraulic pressure.
For mot, you pump the pedal, then start car, and check pedal drops. This is checking servo operation.

Servo's can leak, the one way valves can fail on the vac line. Vac pumps can fail. You can do a leak down test on a servo with a pressure gauge and mityvac.

Master cylinders can leak internally, though pretty uncommon.

Abs modulators can fail, they will usually throw a light for valve operation. Easy enough to test if abs is working.

A bulging flexi can cause these symptoms, the pedal dropping as the hose bulges.

As for fancy fluid. There is no need for an average car, even for occasional track use. I run ATE super blue, I do track days, with 4 pot brembos, and Project Mu HC800 pads. And have zero brake or fluid issues.
Rbf and the like requires changing more often, and has marginal benefit in real world use, certainly not on the road.

I would not be trying to swap out modulators for different ones. Mechanically, it's not the end of the world. But electronically, it's a night mare. Not knowing how Hondas run, generally, the abs will link in to the engine and traction control modules minimum. The software will be brand specific.



If

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[honda_saj]

Or could be pads as well as jon it seems after new pad you have issues ?

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[burbleboy]

I have also checked my brake pedal for 'pedal creep'. Holding pedal down hard when engine off and running. Pedal solid when off...and slowly went down when running. Mechanics at my work says thats normal.

What is strange is that i would like my pedal to be the stiffness when i re-pump it during heavy braking. This is what confused me!

 

[freddofrog]

I would not be trying to swap out modulators for different ones. Mechanically, it's not the end of the world. But electronically, it's a night mare. Not knowing how Hondas run, generally, the abs will link in to the engine and traction control modules minimum. The software will be brand specific.

you're correct
diesel has Bosch ECM and ATE ABS/VSA unit
petrol has Honda ECM and Nissin ABS/VSA unit

Is there any way that pressure can be lost due to air in the ABS/VSA unit without code being thrown ?

list of ABS/VSA codes here --> http://typeaccord.co.uk/forum/topic/23513-vsa-to-be-or-not-to-be-that-is-the-question-lol/?p=244588
you probably know that they cannot be read with a "cheap" OBD2 reader --> http://typeaccord.co.uk/forum/topic/23543-obd2-scs-absvsa/

 

[Rom]

Anythings possible with cars The air would compress, which could cause an issue. Whether that would throw a fault, i dont know enough about the systems to know.
An actuator / valve is what usually goes. So the pump wont be able to control and divert pressure where it wants.

Air can cause issues in the modulator, its why most have a bleed procedure. In a non active state, the modulator is doing very little (on an old car like this) its when traction and abs start kicking in, it works its magic.

To the OP.... does the car actually stop fine? The creeping pedal when running is normal. More pressure on the pedal after an application isnt uncommon, depending on pressure built up, how fast you reapply etc. Im wondering if there really is a fault, or if this a placebo.

 

[burbleboy]

Anythings possible with cars The air would compress, which could cause an issue. Whether that would throw a fault, i dont know enough about the systems to know.
An actuator / valve is what usually goes. So the pump wont be able to control and divert pressure where it wants.

Air can cause issues in the modulator, its why most have a bleed procedure. In a non active state, the modulator is doing very little (on an old car like this) its when traction and abs start kicking in, it works its magic.

To the OP.... does the car actually stop fine? The creeping pedal when running is normal. More pressure on the pedal after an application isnt uncommon, depending on pressure built up, how fast you reapply etc. Im wondering if there really is a fault, or if this a placebo.

The car stops fine mate but i just feel that with brakes being 'properly' bled via Honda, coupled with my brake upgrades, i expected better performance from them under extreme braking. It is maybe me being too fussy, but will go down the braided hoses route like i have done before. When they get done, i will ask Honda to investigate a proper bleed of of the modulator/vsa pump.

I had same poor braking with my civic, the braided hoses cured that (it had all the exact same mods as Accord) If not then hey ho, wont need to worry about brake hoses come MOT time

 

[Rom]

Greenstuff pads aren't up to much tbh. More just a brand that caught on.
But they shouldnt feel worse than oem really.

The problem with brake upgrades, is they aren't always better than oem quality. A lot of places will buy cheap blanks, that they groove and what not.

I'd be looking to have the brakes checked on a roller tester. To see if there's a sticky caliper. We're any of the old pads worn unevenly, or discs corroded?

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[burbleboy]

Greenstuff pads aren't up to much tbh. More just a brand that caught on.
But they shouldnt feel worse than oem really.

The problem with brake upgrades, is they aren't always better than oem quality. A lot of places will buy cheap blanks, that they groove and what not.

I'd be looking to have the brakes checked on a roller tester. To see if there's a sticky caliper. We're any of the old pads worn unevenly, or discs corroded?

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Ive always used Green Stuff as no point in getting Red stuff etc, as thats overkill.

Old brakes were fine, no uneven wear and discs had slight lip. Caliper free and slides re-greased etc....as everyone would do!

When i have time i will take pads out and check them. If bad i will buy OEM pads