During our trip to Hollister Hills I experienced a front braided brake line failure.   

These lines had been in use for about 3 months and this was the first off-road trip with the line.    These are the replacement Pro-Comp / Earls brake lines that 4 Wheel Parts sells for lifted Tacomas.   If you are running these lines you should read and know about this potential problem!    If the line fails, you can loose ALL BRAKES!  

THE BOTTOM LINE: If you have these lines and aftermarket coilovers such as Kings or Donahoes (maybe others) you have a problem!

The Kit that I purchased from 4 Wheel Parts comes in a 3 line pack: 2 new lines for the front wheels and one rear line for the rear axle.   

 The place that they failed is not subject to any movement or pressure, since there is a fixed mounting point above it and the banjo fitting below it.   Because of this, the area that failed is not subject to stretching if the line is overextended, nor is it made to flex or bend as the front wheels are turned side to side.  All of the movement from the steering and suspension takes place above the fixed mounting point.   It is also up above the suspension and protected from trail obstacles.   

When the line failed, I lost ALL brakes, not just the front.   I was able to limp the 1/2 mile back to camp with low range and the parking brake.

More info is below about loosing all brakes...

Here is the passenger side with the other line still intact.   The arrow points to the area the failed on the drivers side.   As you can see, because of the fixed mount in the line above the banjo fitting, this area is not subject to movement or stress.

Click the picture to enlarge it.

The next few picture are picture of the part off the truck where you can see where it failed.   The failure took place inside one of the factory crimp connections.

Click the picture to enlarge it.

Click the picture to enlarge it.

We could not find a replacement line, so we had to make something up to get home.   I used a bolt, 2 washers, a nylock nut, and the 2 copper washers that go with the banjo fitting and some JB Weld.   The line we used was from a Suzuki Samuri.   The fittings were the same as the Tacoma and would have worked if the line would have been long enough.   

I first packed the hole where the brake line comes into the banjo fitting with JB Weld.   I then coated the theads of the bolt and put some more into the banjo bolt hole.   I put it together and tightened it down and then put some more JB Weld on the outside to further seal it all up.   Once it was all together it looked like this.   After a few hours of drying we put it on the truck.

Click the picture to enlarge it.

To keep any dirt or dust out of the caliper, I put the broken banjo back on.   Where the hole where the brake line should have come in I sealed it off with a small piece of paper towel.

Click the picture to enlarge it.

The emergency line was installed and secured to the fender well.   Although it did not leak and we had some feel to the brake pedal again, we had no left front brake so the truck wanted to make a hard right when you used the brakes.   The 3 hour drive home was interesting, but we made it.

These Pro-Comp lines were installed when I installed the Tuff Country 5 inch lift.   I called 4 Wheel Parts (they are the same company as Pro-Comp and sold me the parts) on 6-14-2004 and asked them about the failure.   The item:

Pro Comp Toyota Brake Lines Line
Manufacturer: Explorer Pro Comp

96-98 4wd Tacoma

Internet Part #EXP7213


Designed to replace stock rubber brake hoses on vehicles with increased ride height of 4" to 6". Steel-braided lines will not swell under increased braking pressure demanded by larger tires. They help to deliver quicker, more positive response. Kits are packaged as complete for front and rear of vehicle.


I spoke with Mark at 4 Wheel parts (800-337-9005 ext. 5913) and asked him about the failure.   He looked at the pictures (on this page) and told me that the line was covered by a lifetime warranty and that he would be happy to send out a replacement line.   I wanted to find out if this was a problem or just a one time incedent and Mark referred me to Kirby at Pro-Comp.

I called Kirby (800-776-0767) at Pro-Comp and talked to him about the line failure.   I explained how and where the failure had occured and asked if this happened often.   He said it was a rare fluke.   They sell a lot of brake lines and with all the lines they sell they have about 1 failure every 4-5 months.   He said that I should go buy a lottery ticket since I had a better chance of winning the lottery than having a line fail again.

I called Mark back at 4 Wheel Parts and he is going to send out another line today.

I then called Toyota and asked them about the brake proportioning valve.   I thought this was a 30-40 year old piece of safety equipment that all cars had.   It is designed to close off either the front or rear brake system in the event of a line failure, to prevent a total loss of brakes from a single point of failure just like I experienced.   I called Hansel Toyota in Petaluma and asked about this problem.   While I waited for a call back from the local dealership I called the Corporate number (800-GO-TOYOYA) and asked about the brake proportioning valve.   They looked into it and said that the vehicle was equipped with the valve.   They recommended that I take it to a dealership to have it checked out.     I talked to the local dealership again and they are looking into the proportioning valve, how we can test it to see if it is working and if not why.


I called the dealership back in the afternoon as they had not called me back yet.   The local dealership wanted me to bring it in and drop it off for a day so they could test the brakes.   I asked what they were going to do but they could not tell me, other than "check them".   I asked what they were going to check and they said "the brakes".   It really sounds like they dont know what they are going to check.    I am not really interested in them having my truck for a day if they dont even know what they are going to check, so I called another dealer.   At the second dealership I was put through to the head mechanics voice mail and told to leave a message and he would call me back.   So again we wait!


Still no word from Toyota.   The replacement brake lines from 4 Wheel Parts / Pro-Comp arrived today.   

I installed the new brake line and bled the brakes.   Installing the line and bleeding the brakes only takes about 30 minutes.

In this picture the wheels are turned all the way to the drivers side (left turn).   You can see that there is nothing that is anywhere near the line.

Here is the passenger side with the wheels still turned all the way to the left (drivers) side.   There is still plenty of room between the line and the coilover.

This is now back on the drivers side with the wheels turned all the was to the right (passenger) side.   You can see again that there is plenty of room between the line and coilover.   I took the picture from down low looking up so you can see that there is nothing that the line would hit when the suspension moves up.   

Just to be 100% sure I will flex the truck out and take more pictures!

The passenger side with the wheels turned all the way to the right (passenger) side.   Again, plenty of room for everything.

I did not hear anything from Toyota today, so I guess I will call them tomorrow.


Still have not heard from the local dealership, so I called the service writer where I purchsed the truck. Dave B. (service writer) is also a fellow off-roader and has the Pro-Comp lines on his ride. He said that I should have still had rear brakes and he will look into it and let me know what he finds out.


I got a call from Dave B. at the dealership.   He said that he looked into the brake system and found out that with only one failure like I had you will loose all brakes.   This is due to the ABS system.   The two lines from the master cylinder have to go throught the ABS pump, this is where the "problem" lies.   The front and rear sides of the master cylinder are mixed here in the ABS pump, putting the two seperate sides of the brake system into one big system again.   This why when you have a single point of failure, you will loose all brakes.    I dont know why we have taken a step back in the safety department with this system, but I will look into it further.


During the Takeover trip I had another brake line failure.   This time it was on Drive Shaft Hill on the Eagle Lakes / Fordyce trail.    I had a spare this time since they had sent out a complete set, so I swapped the spare on and finished the trip.   This was on the third day of off-roading.    Once again, it was the drivers side front line that failed.

Because this was the second time the line had failed, I wanted to make sure that there was no interference.   On the ground, with the wheels turned all the way to lock, there is plenty of clearance.   

We went over to Big-O Tires in Petaluma and put the truck up on the lift.   With both the front wheels at full droop, there was plenty of slack in the lines.   If you turn the wheels all the way to one side with the steering wheel (not by turning the wheels by hand) when it hits the steering stop, this is what it looks like.   There is still clearance, but it is tight.   The only thing I can figure is that if you are under extreme droop and also have pressure on the wheel to turn hard, like a rock is pressing the whel to turn, it must flex the front suspension components and in essence turn the wheel even further, which would cause a line failure like I have had.   This is figuring that the pressure of an obstacle can make the wheel turn about 1/4 past the steering stop.

With the stock struts, this would not be a problem, but with aftermarket coilovers, I guess it is.   The Pro-Comp lines will be coming off and new ones will be going on!


We know that this is a problem with both Kings and Donahoes, but dont know for sure about other brands of coilovers.   If they have a similar lower mount, then you should look into it.

The Solution:  I had some custom lines made.   They have different end fittings on them that should solve these problems. They were also cheaper than most lines that I have looked at.    Click HERE to find out more about them!

Back to the Tacoma Page
Back to the Home Page