i just got done helping my friend change his front brake pads and the pedal felt kinda mooshy. so to solve the problem, i bled the fluid thinking that there is air in the lines. well, it worked but after a few minutes of driving and braking the pedal is mooshy again. its a 91 crx SI. what could be cause of this?

 

bleed them again and check your fluid level afterwards...

 

fluid level is fine..i bled them twice already. should i go for 3 times?

 

If it was fine right after you bled them, then became soft. Air is getting into the lines, I'd check for leaks...

 

Air's getting into the lines somehow.

 

Possibly could be the caliper piston seals...couldv'e damaged them when you pushed it back in to fit the new pads. Also make sure you have the shims on the pads, paaatna.

 

thanks guys. i just bled them again. ill see how it holds up this round.

 

when u bled the brakes did u floor the pedal or only go halfway, if you floored it... your master cylinder seals are now toast and you need a new master cylinder

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr.Saturn &raquo;</TD></TR><TR><TD CLASS="quote">when u bled the brakes did u floor the pedal or only go halfway, if you floored it... your master cylinder seals are now toast and you need a new master cylinder</TD></TR></TABLE>
Just curious as why you said this.Is there something special about these,cuase the normal way to bleed brakes is to the floor.

 

my experienced guess is that your caliper pistons are corroded and pits and gunk that built up on the outer rim of the piston that was pushed all the way out is now pushed in and rubbing on the seals letting air into the calipers. youre going to have to rebuild or just buy rebuilt calipers. rebuilding would mean getting new pistons and installing with new seal, kinda tricky the first time, but easy once you know how. tho a lot easier to just buy rebuilt.

 

When you pushed the caliper piston in to put on the new pads did you take the master cylinder cap off? If you floored the pedal while bleeding the brakes you did it the right way dont worry. It sounds like you need a master cylinder no matter how it happened.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Lil Red CRXsi &raquo;</TD></TR><TR><TD CLASS="quote">
Just curious as why you said this.Is there something special about these,cuase the normal way to bleed brakes is to the floor.</TD></TR></TABLE>

That is totally incorrect, when you bleed brakes you never EVER touch the pedal to the floor. The reason is, the system is open, when you floor the pedal the piston in the master cylinder moves more than it normally can and can touch corrosion in the end of the cylinder, this breaks it loose, and tears the master cylinder seals.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by black96ctr &raquo;</TD></TR><TR><TD CLASS="quote">If you floored the pedal while bleeding the brakes you did it the right way dont worry.</TD></TR></TABLE>

Read a few shop manuals before giving advice you sound so sure of... a master cylinder can cost around $200 to replace unless you do it yourself. It was information like this that fucked up my whole brake job the first time I did it; when I took the master cylinder apart to look (I thought the shop guy was full of **** also) there were things as big as little rocks in the end and they had indeed broken free and caused my pedal to feel mushy when the seals tore.

 

if the master cylinder seals are torn, the symptom to look for is a sinking pedal applying constant pressure. theres no reason to think the MC is at fault unless this is so. but i do agree its not proper to push the pedal all the way when bleeding. 3/4 is standard.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson &raquo;</TD></TR><TR><TD CLASS="quote">if the master cylinder seals are torn, the symptom to look for is a sinking pedal applying constant pressure. theres no reason to think the MC is at fault unless this is so. but i do agree its not proper to push the pedal all the way when bleeding. 3/4 is standard.</TD></TR></TABLE>

Agreed, dropping pedal is more commen, but at first can just be the mushy feel, thats how mine was at least, and was right after bleeding 4 new loaded calipers.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson &raquo;</TD></TR><TR><TD CLASS="quote">my experienced guess is that your caliper pistons are corroded and pits and gunk that built up on the outer rim of the piston that was pushed all the way out is now pushed in and rubbing on the seals letting air into the calipers. youre going to have to rebuild or just buy rebuilt calipers. rebuilding would mean getting new pistons and installing with new seal, kinda tricky the first time, but easy once you know how. tho a lot easier to just buy rebuilt.</TD></TR></TABLE>

how can u tell by looking at the calipers and be able to tell if the seals are no good? there is still a mushy pedal when braking. hes gotta pump the pedal about 3x to brake.

the pedal builds up pressure and it seems like the pedal just depresses after a few inches from the top.

 

the only way to tell is to take the piston out of the caliper and check, but at that point, youre gonna have to put a new seal in anyway, and probably have to get a piston anyway, which basically equals a whole rebuild.

like someone mentioned, air is getting into your system, and repeatedly. based on the fact that you just changed your pads, the piston went from a position of mostly exposed to corrosion and brake crud, to back into the caliper within the seal. and yeah, it could be youve damaged your MC by improperly bleeding. but a bad MC like i said would be evident at braking during stoplights or something.

something else to check is if theres simply a leak in the brake lines. youd see brake fluid leaking of course. but it would be really evident if that was the problem...

lastly, some pads are softer than others. could be just that you got soft pads. but if the pedal feel is changing soon after just bleeding, not likely.

 

heres something different. when the car is cold, the brake pressure is just fine. but after that hes driven around and the car warms up, the brakes go mooshy again.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr.Saturn &raquo;</TD></TR><TR><TD CLASS="quote">when u bled the brakes did u floor the pedal or only go halfway, if you floored it... your master cylinder seals are now toast and you need a new master cylinder</TD></TR></TABLE>

This statement is totally FALSE

I am a mechanic for Honda and I can guaranetee you that this is balogna.

 

It is a little hard to try to diagnose something like this without actually being there to look at things.

The first place I would check is the caliper slide pins. I would make sure that they are all sliding properly. You should remove them from the calipers and make sure they are not pitted. You will probably see that they have some grunge on them from over the years. Get some brake clean and soak a rag with it and run the pins in and out of it until you get a nice shiny surface back. You should also try to shoot some inside the hole where the pin goes and try to get as much grunge out of there as possible. I have a small wire brush that fits inside that hole and I use it to clean it out. Once that is all done ... you can lube it with white lithium grease ... not much ... just a coating to make it slide smoothly.

I am not guaranteeing that this is what is wrong ... but the pins not being free will give you the symptoms you are talking about.

Keep us posted.

 

does it go back to "fine" again when the car is cold??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mwkirchner &raquo;</TD></TR><TR><TD CLASS="quote">

This statement is totally FALSE

I am a mechanic for Honda and I can guaranetee you that this is balogna.</TD></TR></TABLE>

Honda Mechanic or not, ripping apart the master cylinder and seeing results speaks for itself. Any book on modern brakes, and most service manuals will tell you not to drop the pedal to the floor. Also if you buy a remanned master cylinder (or even the calipers when I got them) they will usually come with a printed guide and the ones I have seen all warn about the same thing. Why take a chance when moving the pedal halfway works all the same? Sure it won't ruin the master cylinder everytime, and on newer cars this problem may have been addressed (on ABS cars I have no idea), but why chance it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mwkirchner &raquo;</TD></TR><TR><TD CLASS="quote">It is a little hard to try to diagnose something like this without actually being there to look at things.

The first place I would check is the caliper slide pins. I would make sure that they are all sliding properly. You should remove them from the calipers and make sure they are not pitted. You will probably see that they have some grunge on them from over the years. Get some brake clean and soak a rag with it and run the pins in and out of it until you get a nice shiny surface back. You should also try to shoot some inside the hole where the pin goes and try to get as much grunge out of there as possible. I have a small wire brush that fits inside that hole and I use it to clean it out. Once that is all done ... you can lube it with white lithium grease ... not much ... just a coating to make it slide smoothly.

I am not guaranteeing that this is what is wrong ... but the pins not being free will give you the symptoms you are talking about.

Keep us posted.</TD></TR></TABLE>

caliper slide pins?

sorry but i dont know what those are so im gonna guess..are they the bolts that are greasy when u pull them out? hope that helps but my shot in the dark.