additude

I want to flush the brake lines and was wondering what type of fluid to use. Maybe synthetic? something else or should I stick with OEM?

Thanks.

RA40

iTrader: (6)

When I changed the fluid on ours at 60K, I went with Valvoline synthetic. You can always use the recco'd Toyota stuff.

mlevk

I did mine , and used the regular DOT-3 fluid.
The pedal feel was much stiffer after I flushed it.
I think the synthtic stuff has some campatible issues
with the anti-lock brakes on some cars ?
But if you don't drive your car with repeated hard
stops like your are racing , then I think the synt.
is really not necessary .

Lexkost

An easy short-cut to flushing the brake lines is use a turkey-baster to remove the fluid from the master cyclinder an put in new run it like that for a couple for months and repeat process...........This is a procedure for people that are unsure of the proper way to flush lines.

additude

After flushing my brakes with the Synthetic they do not feel as "Positive", if that's a good word to use. They work fine, they just feel less grab ***. If you know what I mean.

With that said, I am going to pick up some regular DOT 3 and re-flush.

BTW, removing brake fluid from the brake reservoir and replacing it is not a flush by any means. The new replacement fluid will never migrate to the caliper piston chambers unless there is a way for the fluid in the piston chambers to discharge and be replaced with new fluid.

If you don't bleed the lines and replace the fluid in the lines and piston chambers you've done nothing but waste time and money.

mlevk

I agree with Attitude on the flush of the reservoir.
The fluid does not get replaced in the lines , and
the master cylinder does not get fluids
replaced as well . So the new fluid just stays in the
reservoir.

As to your feel of the brakes , the biggest problem is
getting air trapped in the lines . I bought a vacuum
pump to bleed my brakes , I don't know if it is better
than the pedal pumping method, but I wouldn't
suspect that the feel should be too different between
the fluids.

additude

A Vacuum pump? I want one. Is that a one man job to use?

I never knew there was something like that.

Makes sence though.

mtsao

There's another way to bleed your brakes that should only be a 1 person job. The trick is to attach a small diameter tube to the bleeder screw and place the other end in a small jug or bottle of brake fluid. As you pump the brakes, the air will be expelled from the system, but as long as you keep the open end submerged (with clip or tape), you will not be re-introducing any air into your lines. You will still have to go back and forth between the hub and the driver seat, but at least you can be confident that no air will get into the system. This is actually also the 'proper' way to do it even with 2 people. Just make sure that the brake fluid in the container is not contaminated.

Mike

additude

Ummm,

What do you do when you have to release the brake pedal and it sucks all the fluid you just pushed out into the bottle back up into the system???????

That's why it's a 2 person job, because someone has to close the valve while the brake pedal is still depressed

mtsao

Additude, with the method I described, the working assumption is that having the old fluid sucked back into the system is preferable than air. If the fluid expelled is so contaminated that you'd not want it back in the lines, then perhaps a total system flush is in order.

Did I misunderstand somehow?

additude

Actually I am not assuming anything. When you have the valve open, with a tube from the valve to a container filled with brake fluid, and you are the only person in the operation, you would have to first, open the valve, then physically re-locate your person to a position which allowed you to push the brake pedal to the floor, forcing the fluid out of the valve and down the tube. Provided you were able to discharge all of the air in the tube on the first full depression of the brake pedal, you would be unable to close the valve,which would disallow any fluid to be drawn back up the tube and back into the piston chamber. This is because your foot would be holding the pedal down to the floor.

If you release the pedal and all of the air in the tube was not fully discharged, then you stand a chance that you will draw the air left in the tube back into the system. Now, providing the air in the tube was fully discharged, then you would draw as much fluid back into the system that you initially discharged by pushing the brake pedal to the floor.

The law of physics says, that if you discharge say 1/4 to 1/2 oz of fluid by pushing the brake pedal, you will draw 1/4 to 1/2 oz. when you release the brake pedal.

Aside from that, the longest path from the reservoir to the caliper piston chamber holds at least 3 oz of fluid. That being the case, then all you are doing is moving 1/4 to 1/2 oz of fluid back and forth by pressing the brake pedal and releasing it with the bleed valve open. Your just moving that fluid from piston chamber into the tube, then from the end of the tube, back into the piston chamber, back to the end of the tube, back to the piston chamber, and so forth for every brake pedal push to the floor and release. It's even possible you are doing nothing but moving fluid back and forth in only the tube. Depending on the length of the tube your actual discharge of fluid from the tube may be extremely small.

Your not accomplishing anything except moving the same fluid from one point, the end of the tube, back and forth.

mtsao

Additude, you have an excellent point. I've conveniently forgotten the fact that it does take several pumps of the pedal for maximum effect. And depending on the length of tube, yes, it's possible that brake fluid is simply being moved back and forth. However, I would like to think that those of us inclined to work on our cars have enough common sense to minimize the length ot tubing.

Provided that the fluid is clean enough not to require a complete flush, I don't why it's so undesirable to have some fluid sucked back in...

Mike

additude

Beats me,

I don't know what you think we are talking about here, but what we are talking about here requires more than one push of the pedal.

What are you talking about?

mtsao

Nevermind me please--I don't know what I'm talking about. Have you had a chance to replace the synthetic yet, and does it feel better with the DOT-3? I've also seen DOT-4, is there any harm in replacing the system with DOT-4?

MIke

additude

No I haven't yet. I picked up 2 cans and a suction blub today so I can try and see if I can do it alone. I will do it tomorrow along with the fuel filter.

Today I had the power steering pump replaced.......

As for DOT-3 and DOT-4, I can only say that I think DOT-4 is better than DOT-3, but I couldn't tell you the difference. However I am sure a search in the internet will turn up some useful info.