99 s10 pickup - automatic - 4wd - brake problem


Old 03-22-13, 05:33 AM
tevil's Avatar
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99 s10 pickup - automatic - 4wd - brake problem

Hi all. Woke up this morning to my pedal touching the floor and a pretty bad brake leak coming from what appears to be the front of my truck underneath.

Does not appear to be leaking in the back.
Opened the hood and checked the master cylinder which appears to be split in two portions inside. The back half was full and fine where the front was empty. I have never seen an MC like this and can only imagine the 2 halfs mean the front and back of the truck. Or primary secondary like a radiator fill.

It appears that neither caliper is leaking but pouring out from the middle front portion of under the engine. Was dark so I couldnt really get in there, but will look tomorrow.

Was wondering if anyone has some insight on possible places to start to cut my time down as I also have to do some work on my toyota and not really big on time.


I have done brake work before but if this is something big I might just bring it in, but could really use saving the money at the moment, even if that just means buying my own parts and diagnosing.
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Old 03-22-13, 05:47 AM
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Sounds like you've broken a front brake line; you'll probably spot it pretty easily when you get a good look. Likely a rust-out based on your location.
Old 03-22-13, 05:51 AM
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Its probably the line attached to the frame on the behind leftside tire. There is a clamp there that usually rust the kine out. I removed the clamp when I replaced mine.

Two lines coming from the abs module. You will need to get 4ft lines, a bender, and flaring tool if you are doing yourself.

Thats what I did anyway... Looking for the pics. will post when I find them.

( Found the radiator pics so I am getting close).

I would buy the all aluminum one next time.

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Old 03-22-13, 05:56 AM
tevil's Avatar
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been looking online as well. I will def check the lines. I have done them in the past, not a big deal also if you've got some plumbing exp lol.
Im hoping its not a "proportioning valve" as it appears to be a pricey part.
Sucks I just took the thing off the jacks a few weeks ago from changing the drivers side joints, bearings and axel.

Ill try to take some pics tomorrw if I can.
Thanks guys
Old 03-22-13, 06:12 AM
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I removed my drivers tire and replace from there. Again look for where it clamps two lines to the frame.

If you follow this line right you will see. Its where they commonly leak from,,,( S10's that is)

Sorry pics are from camera phone.

Even if this is not your issue here are some pics.

Brass coupling you will need to save. Sprayed with pb blaster.

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Its the two smaller lines coming from the abs module here.

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You need to do away with all that coiling.....Two of them anyway.

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Only one had a hole but the other was so corroded I changed them both.

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Hope this helps.
Old 03-25-13, 04:55 AM
tevil's Avatar
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hey guys thanks for the replies.
BOY was I way off. It seems that the leak is actually the rear drivers caliper. Think the piston seals are pretty blown.
I traced out all the lines and found no holes or rot or anything but then made it to the back calipers and sure enough the one in question was covered in fluid. It appears to be a sloooooooooow leak and must have been happening for a while. Im going to get 2 new calipers and pop them on. I need to get the rear caliper tool from my buddy and it shouldnt take me long to swap and bleed.

It seems the fluid I though was brake fluid must have been some oil from the oil filter dripping and mixing with water. But dark at 6am thats pretty suspicious.

Thanks a bunch. I actually refilled the master and pumped the breaks a few time and wham back to normal. Im betting the old owner new about this and was refilling as needed since really its been MONTHS and lots of 4WD over the winter before I noticed anything.

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