Brake problem

myrns, Feb 21, 9:32am
Have replaced master cylinder on eg honda civic I bleed the brakes yesterdaytest drove everything worked fine, then got home at 4pm today to go get re-check for wof and the brakes now go to floor when car is running, when pressing hard the brake pedal just keeps slowly travelling to floor yet feels fine when car is not running, checked all the connections and nothing appears to be leaking could there still be air in the lines for it to do this! or something else!
jasongroves, Feb 21, 9:47am
Have you checked the slave cylinder!
Could be an air lock and still a strong possibility of a leak somewhere or air getting in.
Was it a new or re-kitted master cylinder! Or a 2nd hand unit!
myrns, Feb 21, 9:51am
2nd hand doesn't appear to be leaking, though have been thinking of getting the one I took out rekitted, would of done this in the first place butwife "needs her car" and wasn't sure how long it was going to be off the road,looks like its going to be off the road for a while now! lol
mr_lovebug, Feb 21, 9:53am
Are you using the right grade/dot of brake fuild! EG use only dot 4 in the dot 4 system etc.
myrns, Feb 21, 9:58am
yes dot 4
jasongroves, Feb 21, 10:04am
Not to sound rude.but are you sure it was bled properly and in the right order!
franc123, Feb 21, 10:09am
second hand master cylinders are a HIGHLY dodgy proposition, without and stripdown and inspection you simply don't know what it might be like internally, how many k's the car it was removed from had done, or even if it had been tested to the limit in a crash!If its been sitting in a dead vehicle or on a shelf somewhere for sometime, the process of bleeding the system might have damaged the seals due to being dragged across rust and gunge inside the bore. Given that it supposedly bled up properly yesterday its either crook, there is a pocket of air in a line somewhere or you've left a bleed nipple or union partially undone.You should always fit new ones, how much is a life worth!
myrns, Feb 21, 10:12am
not sure what the right order is but stated rf , lf, lr then rr!
myrns, Feb 21, 10:20am
yeah know what you saying but have a cashflowproblem atm, I bought the second hand master cylinder off a wrecker mate, the car was not in a crash and had 154000kms on clock, the cylinder was still full of fluid when I removed, I tell my wife exactely what you say and told her it would cost probably $500 to get a brake shop to do the job or let me do it but car will be off the road for 3 or 4 days while I run round getting the parts sorted but of course this is way too long! So thought I would go 2nd hand to get it all done in one day.
sr2, Feb 21, 10:24am
You might find the only slave cylinder on the car operates the clutch! I think you're confusing slave with wheel cylinders,
jasongroves, Feb 21, 10:26am
Take it back and tell him its faulty.
might even pay to get the wrecker to install for you, so if theres an issue they can fix it there and then.
I could be wrong, but I was always taught to bleed from the furtherest away bleed nipple first. So.master cylinder is on the drivers (R/H) side at the front, then you would start with L/H rear, then R/H rear, passenger side and finally drivers side (closest to cylinder).
If I am wrong, I will soon get flamed.lol.
directorylist, Feb 21, 10:28am
I cant imagine a rebuild kit would be worth more than the life of a loved one, or heaven forbid anyone else.
There are two things in this world you dont cut corners with, brake work and women :)
jasongroves, Feb 21, 10:28am
Yes, I know:) Lol.
I meant check it for leaks since it operates hydraulically. ( I'm guessing).
jasongroves, Feb 21, 10:30am
And Im quite drunk, so any and all advice is 'As is where is'.
myrns, Feb 21, 10:35am
No don't want to take back as it was $20 if I removed myself plus he told me anything else you need just take, so took a couple of other parts so reckon I got a good deal, not only that he will probably think the one I am returning is my old one LOL, will try your system of bleeding, cheers
myrns, Feb 21, 10:42am
true and I have done both, it is quite ironic that they both slow you down!
directorylist, Feb 21, 10:42am
If its $20 for a dud one then not such a good deal.

Whats wrong with the old one! did you price up repair kits!
sr2, Feb 21, 10:47am
LOL, just poured myself a very large Wild Turkey nightcap!
jasongroves, Feb 21, 10:54am
Ahh, a fine choice.
On the beers myself, got work tomorrow (in a pub of all places), so might have a wee Turkey when I finish;)
myrns, Feb 21, 10:58am
the old one failed on wof as it was leaking, the one I got from wrecker had no signs of leaking and the problem may not actually be the master cylinder thats in it now as I am thinking there may be air in line, though after what you guys have said I will get a repair kit tommorrow just to be safe and to eliminate a possible problem
tmenz, Feb 21, 8:10pm
Hi, had this problem on my Ascot with the original cylinder. It was intermittent - most of the time it was fine but occasionally would sink slowly to the floor. Obtained a replacement piston and seal kit, fitted it and all is now good. The bore was in good condition with no scoring so didn't need a new cylinder.
Examination of the old seals showed deterioration and feathering of the edges on one of them so this was obviously the problem. Cost of the kit was about $75 from memory - cheap for a brake fix. Replaced all the fluid at the same time.
reaperssoul, May 14, 12:09pm
proper way to bleed any brakes,is Rear left, R/R, front left, F/R,the golden rule is the farthest from the brake pedal should be bled first