UKDM Civic Sport - Brakes never feel good - FIXED! - BROKEN !- FIXED!

[ScottUKDM]

Hopefully someone has a similar experience. Car is a 2017 UKDM Civic Sport (1.5t CVT), 45k miles, we've owned since it was 22k miles old.

Around 30k miles, I replaced all the discs and pads (both brembo branded) as the pads were low and the discs were half worn. The rear callipers were retracted using the disconnect multiplug, power to the motor directly method (rather than remove the motor and turn the spigot method). The car is fitted with the ATE callipers if I recall correctly.

I replaced these with no issues (I consider myself a competent diy mechanic). Given all 4 corners were replaced, it was expected it would take a few miles to bed in and get back to good/hard pedal feel. The hydraulic side of the system was not touched at this time. After a week or so, the pedal feel still never improved back to the original feel, so I assumed that perhaps some harder braking was required. Still no improvement. Considering the hard / hot braking sessions, I decided to then change the fluid using the 2 man bleeding method. Still no improvement. The feeling matches exactly that of having air trapped.

I have since changed all the pads for a different brand (pagid), rebled the system and still no improvement.

I then read the workshop manual regarding the 5x handbrake apply/release, and rebled yet again quite recently. No air came out at all. I was using dot4 ESP fluid (ESP fluid being of lower viscosity to help ABS/VSA systems work properly in lower temperatures).

The brakes still feel spongy, as if air is in the system. When driving If I give the brake pedal half a push, not quite fully release and then re-brake, the pedal feels acceptable for that moment only.

Otherwise, the brakes work fine - I can still stop fine, I can still stop with decent braking power, it still passes all the UK MOT tests regarding braking power/efficiency/balance etc. Just the pedal feel is bad, and the pedal has an increased travel.

I'm leaning towards master cylinder issue but find that hard to believe given the age of the car. I have not yet checked what the flexible hoses do when the brake pedal is pressed whilst the engine is running - I guess there could be a bulging hose but again I didn't notice anything specifically when doing the 2 man bleed with the engine off - but appreciate that does not put the flexible brake lines under working pressure.

I'm waiting for the CTA Tools pressure bleeding cap to arrive so I can perform a pressure bleed, just in case there is trapped air in a hard to bleed place (I find this hard to believe but cannot rule it out).

Any thoughts or experiences appreciated.

Many thanks,

Scott

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[bluehatch17]

Change the brake lines. Re-bleed the fluid.

 

[GoldClass]

Change the brake lines. Re-bleed the fluid.

+1

Change to SSBH, re-bleed and it will remove the spongy feel immediately.

 

[ScottUKDM]

Thanks both for the suggestions. When the CTA tools pressure cap turns up, I'll try one more pressure bleed (purging each lines in one continuous bleed) just to be sure there is no air trapped.

Just to re-iterate, the feeling is much worse than it was before with probably an inch of extra pedal travel. Are the standard hoses really that bad? Probably a safety issue if so...

If the flexible brake hoses are to blame, it'd really strange because there is no inconsistency in the brake balance. I say this because like most cars, the hydraulic system is split into 2 circuits(FR + LR, FL + RR), meaning that a single failed/bulgy hose would make the braking worse on one circuit only, leading to an imbalance whilst braking. I find it hard to believe that a hose on each of the circuits would fail through age or heat or fluid etc.

I still also cant work out why it went crap in the first place. My only thoughts are that when I wound in the rear calliper using the motor, if the brake hold function was still on when I parked the car, then pressure would have been 'trapped' in between the rear callipers and the VSA module - but I'm pretty certain the car would have been turned off and the pressure would have been released (would be interesting to know if anyone has experience of this). Is the parking brake motor strong enough to build the pressure enough to pop the inner liner of the rear brake hose? It'd have to have been both sides and also for me not to notice (i'm pretty good at noticing when I've ballsed something up). The motor made no undue straining noises or build in straining as it retracted to the home position.

I had a similar poor pedal issue on my 5th gen prelude after many bleeding sessions (due to track days, plus it's an old car). In the end a Master Cylinder rebuild sorted it but that was at the same time as braided lines. Won't make the same mistake this time!

There doesn't seem to be many fk7 braided brake lines for sale (UK or Europe), what are people using and where from?

Will keep you all posted.

 

[Hondanickx]

I can tell that the brembo pads are crap.I changed mine also on my eudm civic sedan which also has the ATE calipers with brembo discs and pads .They never grab as good as the oem ones did.
And they make a squeeling noise whenever the weather is warmer.
I also changed the brake fluid and bleeded all the sides.
I might remove them again and install ATE brake pads or EBC yellowstuff.

Don't forget the clutch cylinder reservoir is the same one as the brake reservoir.So you better also bleed the clutch slave cylinder .
I used a foxwell obd reader to put the car in brake service mode.So it retracted the parking brake on its own.

 

[ScottUKDM]

Well it only took me a few months to get around to it.

So today I broke out the pressure bleeder, filled it up with 3 litres of dot 4 'ESP' fluid and used my new pressure cap as mentioned in another thread ( https://www.amazon.co.uk/CTA-Tools-7030-Cylinder-Adapter/dp/B01MYXAXS5 ) and bled all 4 corners (no clutch - its CVT sadly).

The cap fits well and works perfectly. I pumped the pressure bleeder up into the red zone and kept it between 20 and 25psi.

Given the amount of fluid the car has now been bled through (as stated above, this must be the 4th time of bleeding), I did not head the order or process in the manual this time. Generally the order is important when the system has ran dry, which is not the case here.

I bled 1litre through the front 2 callipers combined. No air came out.

I then, in 1 continuous bleed operation, bled the rears a litre each. A tiny tiny amount of air came out but nothing that gave me much confidence I'd have a firm pedal.

so 3 litres later all pumped through at 20-25psi, stuck the wheels back on and went for a drive, pedal still has this 3/4 inch of dead space. It felt a tiny bit better as you might expect from freshly bled fluid, but the dead space in the pedal travel is still there.

I'm now confident there is no air in the system, there just can't be. Whilst each corner was bleeding, I would tap the lines/callipers/ABS unit etc to help dislodge any air pockets. The idea of using the pressure bleeder (rather than the 2 man method) was that perhaps air was trapped and needed a continuous flow to shift it (there is only so much of a rear line you can purge before the master cylinder fluid runs low).

I have replaced countless pads and discs (and callipers) on many cars, and done many fluid changes, but never had a pedal stay as stubbornly poor as this car.

So a few theories:

1) I don't think it's the the flexible brake pipes. The brake force and brake wear is even. If one pipe was compromised and flexing/bulging, I'd get reduced/delayed braking on that diagonal circuit, and that isn't happening. The braking is consistent and perfectly acceptable at larger pedal inputs.

2) The pressure bleeder, even at 25psi, didn't seem to shift a huge amount of fluid, took quite a while to fill a 1 litre container at the calliper (10 minutes on the rear, fronts a little quicker as pipe run is shorter). Perhaps this pressure isn't enough for a rapid purge. Perhaps I'm barking up the wrong tree and its not an air in the system issue at all. Id have hoped the pressure bleeder was more vigorous, it would reassure me that it definitely purges stubborn trapped air if the rate was greater.

3) when the discs and pads were first changed, and then also when new pads refitted, the EPB was retracted by powering the calliper motor directly with small 12v battery to fully retract the piston . Has anyone ever needed to run a factory re-calibration process at all?

4) Someone mentioned that 'modern' cars often have a function you can call on the scan tool that will assist with bleeding, but I didn't see any reference to it in the workshop manual, so can't see that this would be needed. I don't think there is any air in the system at all (no callipers or lines have been replaced since the car was new as far as I know).

The wife is going to take the honda e to work tomorrow and give me another day to try and sort the civic. I will quickly remove the calliper pins and then the callipers to inspect fully, but I doubt I will find anything amiss in this regard. The car is doing a regular commute and more, anything amiss in the braking setup would have been noticeable by now.

Im leaning towards some kind of EPB issue, as i once had an older car which had a really poor pedal feel, and the only remedy was a little bit more 'adjustment' on the handbrake cable mechanism, firmed it right up... I'm leaning towards the EPB is letting off too much when releasing the handbrake, and this is the slack I have to take up with the pedal.

Sorry for the long post. Just to be clear, the car is not tracked, the brakes used to feel perfectly fine until I did disc/pad change all round. Subsequent bleeding procedures and pads all round replacement again , and more bleeding, have not yielded a decent pedal...

 

[Hondanickx]

I changed out my brake pads a few days ago for ate brake pads.And after using my foxwell nt530 to put it in brake service mode I noticed there is also a ABS solenoid bleed function.If there is air in the abs unit you can not get out in the normal way I guess.
Ever since I changed the brake fluid from stock my brakes never where as good as they where from factory.
I'm going to rebleed the brakes using the abs solenoid bleed function .Maybe this will firm up the pedal again.There's also a ESP bleed function but I don't know if that works .
The ABS solenoid bleed function let's me choose left front right front and the other sides.

 

[pinhead66]

Even from the factory when I first bought my car I felt the brake pedal feel was a bit on the softer side and felt it was a weakness of the vehicle. I changed pads to Porterfield R4-S on all 4 corners and bled the brakes with my motive pressure bleeder. A few air bubbles did come out but the feel didn't change really. In the quest for better pedal feel i added goodrige lines and that improved feel a noticable amount but still not to my liking. Installed super pro front lower control arms with poly bushings and that improved pedal feel even more where it was acceptable for my tastes but still not optimal. Only after going to a bbk with radial mounted fixed calipers did I feel that the peal feel was stiff enough to my liking. And even then I had to do 2 rounds of full bleeding to chase out all the air bubbles.

If you don't want to spend the money for a bbk, I would suggest getting some stainless lines and bushing inserts for the front lower control arms for an economical upgrade.

 

[ScottUKDM]

The car had a perfectly acceptable pedal feeling before I changed the discs/pads all that time ago.

This is not a track car and does not need big brake kit or stainless lines. I have fitted such items to other cars and I know what it can do, but that is not what is called for here (it's a CVT, it's never going on the track, I hate it so much lol, it's the wife's car).

I will double check the rear callipers (specifically the rubber bushing to see if they are swolen or impeding/affecting the movement, perhaps introducing some knock back), my gut tells me the issue is in the rear calliper physical operation rather than hydraulic.

I will report back towards the end of the day. Hopefully today I can pick up a scan tool that allows epb reset and recalibration, and perhaps ABS/ESP bleed modes.

 

[pinhead66]

The car had a perfectly acceptable pedal feeling before I changed the discs/pads all that time ago.

Occams razor applies here and most likely it has to deal with the rear calipers and/or EPB that you serviced. When i changed my rear pads I just disengaged the epb and used a piston retractor tool to compress the piston with no problems. No messing with a scan tool or manually retracting the epb. Have read quite a few threads here where people ran into trouble using those methods. Good luck with fixing the issue.

 

[ScottUKDM]

Update time!

I can conclude that modern cars are witchcraft and they are all terrible...

After driving nearly 200 miles round trip in the Prelude to pick up a scan tool that could cycle ABS and ESP valves, it's finally all sorted.

I bought an iCarSoft CR MAX unit, very reasonably priced (although more than one should spend to change brakes). It's a bit cheap and chinesey, but it got the job done.

I updated it in the house, plugged it into the car, scanned the car, no faults of any kind in any of the modules (engine, srs, abs, body module etc).

Found the command to unwind the rear parking brake, ran that, and then back in again. Did that a few times, pumped the pedal, used the parking brake switch and generally 'worked' it back and forth several times. I only reversed in and out of my driveway 30ft to test. The pedal was no better. I could not find any kind of calibration process to 'set' the handbrake. The controller must be clever and just run it until it see's the current go high then stop...

I then searched the scan tool for other commands relating to ABS/ESP, and found a screen with 8 relevant options.

4x cycle ABS Solenoid (one for each corner)
4x cycle ESP circuit (one for each corner)

when running the operations, the ABS cycling command is quieter, shorter (about 5 seconds) and doesn't seem too vigorous.

The ESP commands start off exactly the same as the ABS counterparts, except after 5 seconds the ABS pump noise is much more vigorous., and goes on for another 5 or 10 seconds, and you can physically feel the vibration through the cars bulk head.

I'm positive the ESP has never kicked in our ownership. You would have to be seriously out of control for the car to engage that I'm guessing but I digress. I had previously managed to get the ABS to operate in between various previous bedding in sessions and bleeding sessions...

The scan tool gives some fairly meaningless info on the screen, like 'press pedal and check ejection'. I ran all the ABS cycles, and then ran them again with my foot on the pedal. Not really sure what you are 'supposed to do', but with my foot on the pedal, after the ABS cycling was complete, the pedal would 'give', that is, it would sink slightly by itself. It proves that there is some kind of pressure vessel inside the modulator that you cannot see and is not visible on the simplified diagrams I have seen and is computer controlled. This would explain why, for all the bleeding in the world, my pedal had an inch of 'give'.

I then ran all the tests several times, with my foot off, and on, the brake. Each time the pedal would 'give' at the end of the test. During the ESP tests I could feel the vibration through the pedal quite strongly.

Without so much as lifting the bonnet or twiddling a spanner, the brakes came back to life immediately, I could tell as soon as I got to the end of my driveway. The pedal was pretty firm, and no 1 inch of play at the top of the stroke. Witchcraft. Burn the witch.....

Another feature of the scan tool is that I was able to view the braking pressure in real time. This pressure must be read from within the ESP/ABS modulator. At the start of the day, the first inch of pedal travel produced no pressure at all (perhaps registering just 1 bar occasionally). There must definitely be something inside the modulator that 'gives' , that got stuck open allowing the pressure to bleed off into nowhere... Now, the brake pressure registers as soon as I touch the pedal. I can muster about 60bar with the engine off, and close to 100bar with the engine running.

To satisfy myself further, I then bought another 3 litres of DOT4 ESP fluid, filled up the pressure bleeder, and then bled all 4 corners at 30psi (the max of my small unit) in 1 continuous flow each. Absolutely no air came out again at all that I noticed except for the tiny bubbles you get from the bleeder threads when not applying finger pressure to the bleed screw.

Make of that what you will, but some of what I describe does resonate with a few posts I've read on here about brakes suddenly feeling strange, or pedal not feeling firm. What caused it I don't know, but it was definitely abnormal, and the scan tool cycling ABS/ESP valves fixed it without lifting more than 1 finger to press the button.

 

[Hondanickx]

Thanks for this !I expected this would be the answer since I have the same problem.Now I know I can solve this with the abs bleed function.Did you needed to open the bleed valve when doing the abs or esp bleed function?
I've only worked on older honda's this is my first new one and I read somewhere they said the abs unit can have trapped air in it and it can not be taken out manually.

 

[ScottUKDM]

Specifically, there was no ABS bleed function on the scan tool.

Mine has options within modules (that is, physical modules found on the car bus when it is scanned with the tool). It finds modules like Engine ECU, ABS, Body ECU, CVT ECU etc. This is where I found module specific options like cycling the valves (within ABS module).

Separate to that part, there is a 'service' section where I can run various service functions, but not related to specific modules on the car. There is one called ABS Bleed, but after it connects, it says the function is not supported. Similar, there is one for EPB Calibrate, but that also has nothing (it seems be more module specific, so found in the modules part).

My brakes were thoroughly bled several times before today. The pedal feel was restored perfectly today just by running all the cycle commands a few times. Perhaps even just once would have sufficed. Maybe even just one command for one corner would have vibrated loose whatever got stuck in the valve block/modulator.

The real trick now is to try and understand why the modulator gets 'stuck' in this state where there is 1inch of pedal give. The car has been like this for probably 2 years now until today, and it started immediately after replacing discs/pads (and probably before the first fluid bleed).

Logically, it must only happen when brake fluid travels in reverse, that is, back up from the calliper to the valve block/modulator, eg when pushing the front pistons back in with a tool, or pushing the rears in using the motor. I cannot recall if it was the fronts or backs that caused it, as I did 1 set one day, and the others the next day, then realised it didn't feel quite right after a bit of bedding in.

So to summarise - if your brakes are physically good (pads and discs in good order, callipers/pads are not binding and fresh fluid all bled properly) but the pedal still feels crap, then something inside the abs modulator is stuck in bypass mode, and cycling the valves seems to magically fix it.

Again, I fixed it just by pressing a button on a scan tool - I did not need to bleed it again today (or even yesterday, or the time before that, or the time before that, or the time I changed the brand of pads, or the time I bled the brakes before that also lol).

In other news, the long journey in the prelude was fantastic and makes up for the issues with the civic. The prelude is slightly track modified with larger brakes, sharper pads, limited slip diff, tein coilovers, fully poly-bushed and shod with extra grippy tyres. It's probably not much faster all-in-all than the civic sport in a straight line, but its soo much more engaging (if not a little harsh ride wise).

 

[arpypat]

Glad you resolved your issues! I read through the forums before tackling my brake job a few months ago.

From what I remember, this is the sequence:

1. Ensure EBP is disengaged prior to shutting off vehicle
2. Replace pads, rotors as needed
   1. For the rear, I wound the caliper piston back manually using one those cheap universal brake tool kits
3. Bleed each corner following bleeding procedure
4. After turning vehicle back on, manually toggle the EBP 5x times

That last step is the EBP reset/calibration. Could've had issues due to skipping that step originally?

 

[ScottUKDM]

From what I recall, the manual states that the epb x5 is to help shift any trapped air (after a calliper replacement for example), and is not for any recalibration procedure. You are supposed to bleed again after the epb x5 as well. I'm not sure if there actually is a calibration procedure at all (if there was one, id expect to have seen it in my scan tool). Plus, many posters on here have been able to replace their rear pads without the epb being crap afterwards (suggesting it requires no calibration at all, its self-setting)

Having re-read my original post, I can see that the pedal was crap after disc/pad replacement but before I bled the system. It must be something to do with pressure going back into the modulator. Perhaps I did one of the piston push backs when the car ignition was on, or maybe brakehold was on after i moved the car around on my drive, and this confused the ABS which then went into some kind of de-pressurisation mode and the valve got stuck or latched or failed to return or something.

Who knows - I don't think we will ever find out. A junkyard modulator is ~£80 and looks like a complete pain to dismantle so my intrigue will have to end there.

A scan tool should show the brake pressure in real time - the tell is if there is notable pedal movement but no pressure - this is the sign that the modulator is stuck in the 'nackered' mode, and a scan tool jiggling all the ABS/ESB valves will fix it. The brake pressure will then show positive significant values with much less pedal travel. Simply activating the ABS through driving did not seem enough for me.

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