1999 chevy silverado ext cab 5.3 abs brakes. I need to know the thread size or type to replace a brakline. it comes from the abs controller under the drivers door near the frame. autozone had no idea what type of line i needed

matty,

Need more information. In (DETAIL), what line are you replacing? Also (EACTLY) what is the (PROBLEM) and how was it DETERMINED) that the line is at (FAULT)? Common thread sizes are 5/16 or 3/8. For this application better to go "OE" (DEALER) or (PROFESSIONAL AUTO PARTS SHOP).

Line is leaking where it goes into the abs controller.There is a connection about 1 foot away so i can bend a new line to replace the fitting at the abs controller to the connection that is already there.

should be a common thread pitch, but flare may be a bubble flare.

matty,

Thanks for explanation. I understand which line it is now. It's really rare for that particular line to leak, but anything is possible. Are you (SURE) the (LEAK) is not from the "ABS Conroller"?

Positive! this line was replaced a month ago by a mechanic not of my choosing because i had to be towed when this line burst. The mechanic overtightned the fitting and probably didn't use the correct line or flare ect ect. so i'm looking to repair it correctly with the correct size line.

hope it wasn't cross threaded.

matty,

Lines closest to the abs controller or master cylinder should not be bursting. The simple reason is that pressure is greatest at the first line coming off the modulator or master. The fact that you stated the line burst, tells me that the mechanic "Rigged Up" something that is not "OE". You gotta restore the lines back to "OE". Again man. See a dealer for the right parts.

matty,

Try this. Disconnect the line that’s leakin. Use a rag to clean off all brake fluid. You gotta get both connections really clean and dry. There can’t be any brake fluid on either connection. When I say both I mean the threads on the fitting that’s attached to the line, and the female portion on the modulator that the line connects to. The next thing is to put a thin coating of a product called “Leak Lock” on both threads. “Leak Lock” is a product that plumbers use to stop leaks. This stuff really works. You can buy it in a plumbing supply store. You won’t find it in a store like the home depot. It comes in a blue plastic bottle, and the product itself is blue. Use a “Flare Head Wrench” to tighten the line into the modulator. You get more turning pressure and a tighter grip with a flare head wrench, instead of a regular wrench. Tighten it really tight then let us know if it still leaks.

Try NAPA for the line.
Check the female portion (and male portion,if you are re-using the current line) for cross-threading.

did you get a chance to try any of those suggestions yet?

Hey, thanks for all the suggestions. I'm curently using another vehicle n plan on working on the chevy this weekend. let ya know how it goes.

matty,

Bleedin the brakes on an abs vehicle is the same as bleedin the brakes on a vehicle without abs brakes. You just gotta be careful that no air gets into the ABS modulator. If air does get in then you’re gonna have to have a dealer run a Tech 2 bleed sequence. You should also check with a dealer about the TSB below to see if your truck is part of the recall. Off the top of my head I think it is.

TSB #02-05-25-006A

yeah, while line is disconnected be sure to keep the master cylinder reservoir full and once you've inspected the internal threads of the ABS controller, cover that opening until you are ready to screw the new line in.

Matty - in spite of the many answers you received I didn't see anyone address your question. I am currently replacing the main line from the ABS to the rear splitter on MY 1999 Silverado 2WD, 5.3 litre. Ignore the responses about "this line should never burst". The statement is true, however GM has a serious, serious problem with the steel lines they installed on our trucks. Do a quick search on "GM truck brake line corrosion" and you will find hundreds of people with bursting brake lines and rotted fuel lines regardless of whether they live in a snow zone or not. I pulled the box off of mine to make the job easier, and the frame is rusted worse than a car that has sat in a field for ten years. I also found that the burst line is only the tip of the iceberg - all five lines from the ABS module really need to be replaced because they are almost rusted through. This is a big job no matter who does it.

Anyway, I measured the fitting that screws into the ABS module itself and found the thread size to be 1/2 - 20 NF for the 1/4" line. This is an odd-ball size in my opinion since the standard fitting on the other end that screws into the splitter is 7/16-24. I was able to clean up and re-use the ABS fitting when I made the new line but I'm afraid my luck might run out when I try to remove the other 4. My removal method for the ABS fittings is to cut the line off close to the fitting and then use a six point socket to turn out the fitting, otherwise I think a wrench might strip the nut. BTW - It is not a bubble flare, it is a standard inverted flare.

Hope this helps and good luck. Rob in Ontario.

Zoo Crew,

I know your tryin to help, but the orignial poster hasn't posted back since 6/1/2011.

Yep - I got that, but alot of people land here because they have the same problem. Even though the original guy has moved on, there will be more trying to figure out why the pre-made tube they bought won't fit the ABS module. I just wanted to let anyone interested know it's 1/2-20 on the ABS end and 7/16-24 on the splitter end. That's all.

Thanks for the good info Zoo Crew!

Zoo,

What happened?
Where are you?
We got postings on this forum from 2008 and before.
You're really late in resurrecting them.

So many things to do, so little time in the day...

There was another guy who did resurrections a long time ago, and he got nailed for it too.

Nobody's perfect.

Thanks for the sunday morning humor....right on time! :)