Brake line size for 2005 Sierra

Subject: 2005 Sierra 4WD 1500 Crew Cab.

My 2005 Sierra, with only 42,000 miles on the odometer (legit - I bought the truck new in December, 2004), has been stricken by the corroded brake lines syndrome.

So far, only one line has burst - a line to the left front brake - spraying brake fluid all over the exhaust manifold and leaving me with rear brakes only.

Before spending the money to replace the whole system, I thought I would for the time being at least render the truck drivable by replacing only the burst section.

I'd like to know, before borrowing a car and heading off to the parts store for a generic length of pre-flared tubing, what the tubing diameter is (i.e. 1/4" or 6mm) and what the thread gauge on the fittings is.

Any help will be appreciated.

A GM parts department can tell you for sure the line size, just call and ask. I'm pretty sure it's metric on yours. The fittings that come with the lines will fit the fittings on the truck. Worst case is just cut the fittings off the old line and use them on the new one, if they are not too corroded.

Subject: 2005 Sierra 4WD 1500 Crew Cab.

My 2005 Sierra, with only 42,000 miles on the odometer (legit - I bought the truck new in December, 2004), has been stricken by the corroded brake lines syndrome.

So far, only one line has burst - a line to the left front brake - spraying brake fluid all over the exhaust manifold and leaving me with rear brakes only.

Before spending the money to replace the whole system, I thought I would for the time being at least render the truck drivable by replacing only the burst section.

I'd like to know, before borrowing a car and heading off to the parts store for a generic length of pre-flared tubing, what the tubing diameter is (i.e. 1/4" or 6mm) and what the thread gauge on the fittings is.

Any help will be appreciated.
Take a piece of tubing with you and a fitting. Match the threads on the piece at the store and your fitting. 6mm is not the same as 1/4 is closer to 6.3mm at least I have a S-K 6.2mm socket for 1/4 nuts on my metric set.

Thanks for the advice, gmtech1. I'll ask my questions of the parts store.

Given what has happened to a vehicle that I expected to last me a long time, I'm not in a friendly frame of mind to talk to the GMC dealership - yet.

I don't anticipate re-using the old fittings because I plan to buy a length of pre-flared tube with fittings. In order to re-use the old ones, I'd have to cut and re-flare the replacement section. Although I have a flaring tool, I'm not confident of its ability to create the type of flare necessary.

My thanks to you too, rhandwor.

I realize that 1/4" is not the same as 6mm, which is why I asked. I put a calipers on the tube and it looks like 1/4", but .2mm difference is too small a difference to be certain.

Yes, I'll be taking the old brake line with me to the store.

Thanks for the advice, gmtech1. I'll ask my questions of the parts store.

Given what has happened to a vehicle that I expected to last me a long time, I'm not in a friendly frame of mind to talk to the GMC dealership - yet.

I don't anticipate re-using the old fittings because I plan to buy a length of pre-flared tube with fittings. In order to re-use the old ones, I'd have to cut and re-flare the replacement section. Although I have a flaring tool, I'm not confident of its ability to create the type of flare necessary.

Don't hate on the dealer for low quality metal. They just sell what they are given. They can assist you in letting you know what size the pipe is, and may even stock some lengths of it. If not, I'm sure any parts store will have what you need.

Not hating on the dealer, but on GM. Chinese steel for brake lines? Aside from that, it's my understanding that new pre-bent brake lines are not available from GM, so someone like me is going to have to bear the labor cost of having a dealer tech make up new lines.

In any event, I've changed my mind about doing a partial fix myself. I drove the truck this afternoon to see just how dangerous it is. Rear brakes only, of course. And the ABS is probably losing its mind because the left rear is locking up on any heavy application. I just hope I can get it to the dealership without rear-ending anyone.

Not hating on the dealer, but on GM. Chinese steel for brake lines? Aside from that, it's my understanding that new pre-bent brake lines are not available from GM, so someone like me is going to have to bear the labor cost of having a dealer tech make up new lines.

In any event, I've changed my mind about doing a partial fix myself. I drove the truck this afternoon to see just how dangerous it is. Rear brakes only, of course. And the ABS is probably losing its mind because the left rear is locking up on any heavy application. I just hope I can get it to the dealership without rear-ending anyone.
Its a job to do it your self I've done a few older cars and its a pain I never have done a vehicle with anti lock brakes. I've never observed a Georgia car with rusted out brake lines. Just northern cars where they used salt or someone who lived along the ocean.