Brakes Failed During Panic Stop

[1990BlackLS]

Hello everyone.

90 LS400, have had the car for many years. No real problems, regular maintenance done by me.

Panic stopped a week ago to avoid an accident happening and the brake pedal went to the floor halfway through the stop. It felt like something let go in the system.

Got some pedal feel with pumping and limped to a parts store a half mile away.

Lifted the hood and saw the reservoir was nearly dry. Looked under car in front, nothing.

Eventually found a huge puddle of brake fluid just forward of the passenger side rear tire. The fluid seemed to be dripping from inside the frame and some other kind of paneled off section that is right about where someone in the right, rear seat would put their right foot, if that makes any sense.

I bought a huge quantity of cheap fluid and limped back home, about ten miles, in stop and go traffic. Three times I topped off the master cylinder. Just ran out of fluid at the house and managed to get her in the garage.

The Lexus dealer provided me with a parts diagram and it shows that the line I might need runs all the way from the front of the car to the back as one solid brake tube that will need to be ordered from Japan!

Is there any way to access the area I am describing to cut out a section and do a properly flared and safe repair?

I may have to cut out the passenger foot well to gain access from what I am seeing.

Thanks in advance everyone.

[SRK]

There is no way I would hack the body to gain access to the line, or repair the existing line. If you are convinced the perforation is in an inaccessible area, then I'd run a new line from the first available fitting, to the next available fitting. You may have to use "joiners" to connect several new lines. Then route them in a safe run without burying them in the body. As to the existing line I'd "abandon in place".

It seems odd to me that the lines would be run in a way to be inaccessible. However I've never really looked at my LS for that purpose.

[landar]

The rear line looks to be part# 47326 in this diagram(the rear brakes are toward the right in diagram). It looks like it would be a chore to replace this line without a lift and some special tools/equipment. Since this is a very serious safety issue, I would try to get help from a shop, perhaps an independent brake shop. I suspect, as SRK suggests, that you would be better off routing a new line and leaving the old one alone. But again, this is probably something you want a shop to do.

Now, if this line was rusted and perforated, are the other brakes lines ready to go? You might want to have the rest of the brake system carefully examined and take appropriate action. I don't know about you, but I would have had to change my shorts if I went through the same type of panic stop and this happened. I would not drive it anymore until fixed and would seek professional help (for the car).

BTW, where do you live? Has the car been driven primarily in the rust belt? And... welcome!

[1990BlackLS]

Thanks for the warm welcome!

Yes it is a rust belt car. I've done a bit of research and it seems it is quite a problem for cars like ours since the undercarriage covers tend have gaps or areas where salt can enter and act like a hot knife of rust and cut the brake tubes and fuel lines with a virtual band of aggressive salt rust.

BMW's seem to be especially prone.

I wash the undercarriage regularly but there is no way I could have cleared salt residue from anything behind those panels even if I wanted to.

That line looks to be a bear to deal with. I am going to disconnect the line at the front and cap the system so I can use the front brakes to get the car around the yard and out of the garage while I figure the exact location of the leak and examine the other lines.

If I pressurize that tube with an air compressor I should be able to listen for where the leak is coming from and get a bore scope into the crevices that are available.

Any ideas or suggestions are greatly appreciated and I will get photos on here as I find out what is what.

I do not have the money for a shop. I did the timing belt myself, this one is just going to be another adventure!

[landar]

It probably will not matter if you can pinpoint the leak or not if the line is largely hidden. If you cannot afford a shop then you need to invest in some bending and flaring tools to fashion a new line. The generic lines and tools are not expensive, you just need some patience to re-route everything. Again, pay particular attention to the other lines and replace if they look suspect.

[lenore]

Harbor Freight tools has those tools cheap....I would run a new line as far on either side where no rust shows.....

[1990BlackLS]

Thanks guys, it is nice to hear the suggestions. There is a harbor freight near me, I will check it out. My idea is that I need to find a central access point (middle of car) so that I get the lines in without resorting to a lift.

The stock line is so long I know it will require a lift unless there is some magic panel that allows it to be put in horizontally.

Part of the reason I want to pinpoint the leak is for everyone else's benefit. I really think I got lucky that I was not in an accident and had easy access to spare fluid to make it home.

Thanks everyone, I will check in again tomorrow morning if there are any other ideas.

Take care!

[1990BlackLS]

Finally had time to get under the car today. The access is limited everywhere, but an aluminum panel near the passenger side muffler gave a bit of room to examine things.

The lines are severely corroded. The rust falls off the lines like rain. The leak was found in the section of the right rear brake tube just as it turns up to go over the differential. I cut out a six inch section that was the worst and the piece just came out with one cut as the other end was holding on by a thread.

I took off the right rear wheel to gain a better view and then noticed that the tube sections higher up in the car are in nearly perfect condition.

The remainder of the rear brake lines travel through the center of the car behind a plastic grid cover. In the diagram it looks like they follow the frame rail, look toward the drive shaft and you will see the brake lines.

It looks like it will be quite a job to fab up some replacement lines, but it can be done. The tubes are of a very small diameter and should be pretty easy to work in and around once I decide where to section the tubes to get them in and around the major obstacles.

IMO if I buy the lines from Lexus, I will have to remove the exhaust and other major components. I'm probably going to install some kind of bypass at the head of the system, I do not want to have to limp home like that ever again!

I'd suggest anyone that lives in the rust belt or suspects they have a survivor from the region, take off their rear wheel and take a look around. This could have easily been a wreck if circumstances had been different.