[pippintook]

I'm helping my brother fix my my mum's 2005 honda civic. About 2 months ago, my mum was having bad bad braking. She didn't call me but went to a local auto chain store and kid said she had no fluid in brake reservoir. He filled up brake brake reservoir. She said it braking was better. I told her bring car to my place and we would check it out. She came by few days later. I crawled under car and tried to look at all lines and could not find any leaks or signs of leaks. The brake reservoir was full. I drove the car and the brakes were definitely a little bit spongy. I said lets monitor and see if it loses more fluid. I checked the car about a week later and fluid level was still the same.
Brakes were still spongy. I thought possibly the master cylinder had somehow got empty and air got into system. I thought maybe do a full
bleed - though I did not do the bleed
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Over the last 4-5 weeks she has not been using the car too much. A few days ago she said braking was getting really bad. My brother drove car and told me brakes were really bad. Very spongy and had to have pedal almost on the floor to stop. He brought the car out to my place. We could not find any leaks and brake reservoir was full. I drove car and brakes were really bad - almost undriveable. He thought the master cylinder had failed. So, we agreed try new one. We installed new master cylinder. We bench bleed it before install. After installing, I went to each wheel while he pumped and we bleed the brake system. Fronts had good flow and some air came out. Back right rear did not have any flow at first when I loosened the bleeder and he pumped. Eventually, it flowed and seemed to generate a moderate stream of fluid from bleeder with no air. I started doing the left rear, got fluid and after some pumps - decent stream with no air. Then, i noticed small brake puddle by right rear. I went back to right rear and he pumped. Now, I saw small tiny stream of fluid come from brake line near wheel cylinder (car has drum brakes in back). There is an approx. 8" steel line from rubber flex hose to wheel cylinder - this line had tiny leak.
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I bent up some new line and replaced. All good - no leaks. We then bleed all wheels. But, we could not really get the brake system to firm up - the brake pedal felt spongy. We first tried manual bleeding at each wheel - each wheel would show maybe a little air bubbles and then good stream with no air. Brakes still felt spongy. I tried my automatic bleeding with harbor freight tool that uses air compressor and sucks fluid out. This also seemed to work pretty good and showed good stream of fluid with no air bubbles - but brake pedal still spongy. We tried bleeding with engine running- manual and automatic bleeding and brakes were still spongy. We thought maybe air trapped in master cylinder , we bleed master cylinder on car but brakes still spongy.
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The car has ABS - we thought maybe some air trapped near in ABS module. He pumped the brakes and held them. The two lines from master cylinder
go into the abs module. When I loosened what is the rear line from MC - i get nice stream of fluid coming out near threads. He pumped brakes again and I loosened what is the front line from MC - i get weak stream of fluid - the fluid just kinda trickles out on the threads. Not sure if that means anything.
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We are not sure if the brake reservoir had gotten completely empty. We thought if the reservoir did get empty - is it possible air got trapped
in the abs module. We tried researching a little online. Honda does not seem to have different instructions for bleeding with abs. I found post on just answer - where a honda tech was advising on replacing abs module on 2007 civic and I can not see anything where the honda tech advises bleeding the abs module.
I saw some posts where guys discuss air in abs module and then drive down gravel road to activate abs module - kinda burb out air from abs module and then bleed the system. Also saw few guys discuss using a scanner to activate abs and this then then forces air out and then bleed. My scanner cant do that abs activation ( no bidirectional support).
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I think I am likely going to take the car to my mechanic. He's great guy and great diagnostics skills - so, I'm sure he could figure it out. But, he's always super busy and often takes him some time to get to things. Anyone have any ideas or advice ?

Thx

[Carl S]

Crazy as it sounds, it's not impossible that one of the rubber flex hoses is bad. They can separate inside.

[JSchmitz]

Could be a bad master cylinder. Did you look to see if it's leaking out of the rear of the master? I've see them leak inside the booster or car.

[necdb3]

I've dealt with air trapped in ABS modules in the past. The best thing to do is, get the best pedal you can with normal bleeding. Find an area that the tires can easily slide. Wet grass is a good example. Drive the car allowing each wheel to slide to activate the ABS. You don't need a high rate of speed! If you get the ABS pump to run and trigger the valves, it will purge trapped air.

[pippintook]

Thanks for replies
.
We replaced master cylinder as it did have very similar symptoms as a bad master cylinder. But, issue was same with new master cylinder - pretty sure the new master cylinder was a dorman. When we replaced the master cylinder - did not notice any leaks at the back. I'm not sure about rubber flex hose - I get pretty good flow at all wheels when bleeding. It was raining here last night - took out car and did about 10 panic stops from decent speed and wheels locked up and I did skid. I'm sure that would activate the abs - but I can not really feel the pedal modulating under my foot - though i thought I could here the abs motor. I came back to house and rebleed the system - with car running and using my har freight bleeder. The car did seem a little better - though I'm not sure how much improvement. My 78 TA - i just touch pedal and get great stopping - same with my 98 TA. The civic seems to travel an inch or 2 before any action and then a bit spongy and then when nearer the floor stops. If I really stand on the brake pedal - it will stop and lock up. It seems to have all the symptoms of air in the brake system. But, I'm 99% sure I have gotten all air out of the brake lines, calipers, wheel cylinders, master cylinder. Only thing I can think of , is that there is air in abs module.

When I see guys bleeding abs online - it seems like they open a brake bleeder valve (bleeder valve goes to hose with container of brake fluid), say they open rear right (RR) bleeder valve and then use their bidirectional scanner and get abs to activate RR solenoid. Then, they proceed and do each bleeder valve in same manner
open RL bleeder - use bidirectional scanner and get abs to activate RL solenoid
open FR bleeder - use bidirectional scanner and get abs to activate FR solenoid
open FL bleeder - use bidirectional scanner and get abs to activate FL solenoid
.
I checked and I can see a bidirectional scanner (like Autel Scanner MaxiCOM MK808) that could activate abs would go for around 500-700?? I work on cars a fair amount. I probably should get bidirectional scanner , i think is almost an essential tool for working on newer cars. I likely need to see my mechanic and see what he says.

[geeteeohguy]

Originally Posted by pippintook

Thanks for replies
.
We replaced master cylinder as it did have very similar symptoms as a bad master cylinder. But, issue was same with new master cylinder - pretty sure the new master cylinder was a dorman. When we replaced the master cylinder - did not notice any leaks at the back. I'm not sure about rubber flex hose - I get pretty good flow at all wheels when bleeding. It was raining here last night - took out car and did about 10 panic stops from decent speed and wheels locked up and I did skid. I'm sure that would activate the abs - but I can not really feel the pedal modulating under my foot - though i thought I could here the abs motor. I came back to house and rebleed the system - with car running and using my har freight bleeder. The car did seem a little better - though I'm not sure how much improvement. My 78 TA - i just touch pedal and get great stopping - same with my 98 TA. The civic seems to travel an inch or 2 before any action and then a bit spongy and then when nearer the floor stops. If I really stand on the brake pedal - it will stop and lock up. It seems to have all the symptoms of air in the brake system. But, I'm 99% sure I have gotten all air out of the brake lines, calipers, wheel cylinders, master cylinder. Only thing I can think of , is that there is air in abs module.

When I see guys bleeding abs online - it seems like they open a brake bleeder valve (bleeder valve goes to hose with container of brake fluid), say they open rear right (RR) bleeder valve and then use their bidirectional scanner and get abs to activate RR solenoid. Then, they proceed and do each bleeder valve in same manner
open RL bleeder - use bidirectional scanner and get abs to activate RL solenoid
open FR bleeder - use bidirectional scanner and get abs to activate FR solenoid
open FL bleeder - use bidirectional scanner and get abs to activate FL solenoid
.
I checked and I can see a bidirectional scanner (like Autel Scanner MaxiCOM MK808) that could activate abs would go for around 500-700?? I work on cars a fair amount. I probably should get bidirectional scanner , i think is almost an essential tool for working on newer cars. I likely need to see my mechanic and see what he says.

You are on the right path. Most Hondas with ABS need a bi-directional scanner to sequentially bleed the brakes and cycle the modulator in the proper sequence. It's not simple.

[Darren 639]

You mentioned drum in rear. Pulling drums off confirm or replace shoes if worn adjust to super close to drum. Pump pedal and re adjust the shoes again. Also it’s not nice for the rubber hoses., but crimping all off should give you a rock hard pedal proving all is well up to the calipers and shoes. Release one at time and see what wheel drop pedal most.

[59safaricat]

As stated above, rear drum brakes that are out of adjustment will cause a spongy pedal. Like most cars designed in the last 30 years, the Civic uses a leading and trailing brake design where the brakes are adjusted by use of the parking brake, not by backing up like the Bendix design. Most people who drive an automatic transmission never apply the parking brake and the rear brakes become widely out of adjustment. Firmly cycle the parking brake a few times and see if the problems disappears.