evil_goat

The brake fluid for me is black/dark brown. Isn't it supposed to be clear? The brakes work, but not as well as a newer car. Does this mean I should flush them?

fb97xj1

Should be clear.

evil_goat

What symptoms would dirty brake fluid cause, and how urgent is replacing it?

boxburn

It's not what it causes but what it means. The darkness in brake fluid can be a sign of rubber and seals slowly breaking down, depositing tiny particles in the fluid giving it the colour. If it hasn't been replaced in a long time, it's likely to have absorbed moisture from the atmosphere so is due a flush. It's not going to cause a brake failure by not replacing it but it should be done to help prevent internal corrosion of the steel parts of the hydraulic system.

robsjeep

DOT 3 or DOT 4 fluid is near clear when new, as it absorbs water it darkens. DOT 5 fluid is translucent purple, it wont absorb water, but has other issues.
you should replace all the fluid (DOT 3/4) by flushing every couple years because of by that time it usually has gotten just under too much water absorbed. absorbed water lowers brake performance as the water lowers the fluid boiling point, which is bad. Also water in the fluid turns the fluid into a corrosive, which will rust your cylinders, calipers, and other metal brake stuff. if your in a dry desert climate, you can go longer than if your in a damp tropic climate. two years is a good time, and it usually assure you wont get enough water in there to cause corrosion, nor significant reduction in braking from boiling point suppression.
black bits or muck in the fluid may indicate rubber bits going bad, and or corrosion.

You need to replace the fluid and then assess the brakes. almost always, replacement of heavily water contaminated brake fluid with new will improve braking, so long as corrosion or rubber deterioration has not set in

In your case, start the flush by wiping off the reservoir or dirt, do like wise to cap. Only then open reservoir and now begin removing all the fluid you can from reservoir , perhaps use turkey baster, with a hose on its tip. if reservoir can be removed easy, then you can clean it well, a must if it is very mucky. If it is lighly dirty with a haze inside, you may wipe reservoir insides with lint free clean cloth. dont allow junk to get sucked into the reservoir outlets however. Then when reservoir cleaned of any muck or chunks, fill with new fresh fluid. then proceed to flush starting at far brake, passenger rear, driver rear , passenger front,and work you way closer to driver front last. Flush till it comes out clean at each wheel.

Your brakes should work much better now,

note if you got some computer on wheels "car" with fancy Anti Skid Brakes, check the "car" specific service procedure for special instructions on flushing brakes. Some new fangeled techie cars have systems which require unusual methods,

cruiser54

One of the most neglected maintenance items in the automotive world!!!
Suck the fluid from the master cylinder with something like a turkey baster.
Fill with new fluid.
Bleed brakes until fluid is clear.
Right rear, left rear, right front, left front.

If you have compressed air available, this tool is the bomb:

https://www.harborfreight.com/brake-...der-92924.html

EEVEE

brake fluid and power steering fluid is always neglected lol

cruiser54

Absolutely. And then we wonder why the components fail......
Fluid levels also. Like transfer case levels never checked. "My transfer case blew up on the freeway!!"

robsjeep

My xfer case has a sight tube for oil level. easy to see seeing as the jeep if lifted.

EEVEE

yup yup ahhh the chain slap inside the case when it has been nearly run dry lol. if i were to guess the 4 fluid are those 2, differentials and transfer case it seems. speaking of i gotta do all that good stuff in my car soon lol

evil_goat

I do have compressed air. Will this be the only tool I will need for the job?

exasemech

A basic Mityvac pump works fine, is useful for a lot of other things and you don't need to worry about the H.F. factor


https://www.napaonline.com/en/p/BK_7...&gclsrc=aw.ds&

robsjeep

NO! Do not blow compressed air into your brake system.
You risk blowing junk into the system, you may blow seals, unless you take efforts to dry and filter the air you may get rust bits, and water from our compressor tank into there, plus you may get brake fluid splash back where you spray air in, and a foggy spray of poison, corrosive brake fluid from the exit point it sprays out of. Save compressed air for blowing out rinsed disassembled system components, carefully.

Instead pump the brake pedal (my preferred method) or use one of them vacuum flush bleeder things, which can work nicely for you too. But no for blasting out the system with an air compressor.

Also, a safety hint, wear safety glasses when doing the brake bleed. Sometimes a bleeder hose blows off the valve, or fluid jets out from the valve thread and will get you in the eye. I can assure you that DOT 3/4 Brake Fluid BURNS THE EYES LIKE FREAKING H.E. DOUBLE TOOTHPICKS! I ran so fast to the water hose to flush. kept flushing for 15 minutes, still burning. had to see doctor. Dont mess with it, wear glasses just as you would when operating an angle grinder, wear them!

Have fun!

robsjeep

I tell you, if they had put a drain plug on the diffs, the fluid would be changed a lot more frequently. On my D30, it has a drain now, both fill and drain plugs are magnetic,. To add the drain plug the case was drilled and tapped, easy peasy. But I got a Ford 9 inch in back, so to get a drain I will need to weld a bung on it, but, it has been armored with plate welded on bottom of the diff case, so a bit more work thus it aint been done yet. So instead now I pump the oil out of the rear end via the fill hole and a slender hose which I work down to the low point, slow, but effective. I have a magnetic fill plug, which does pick up fine wear hairs, so that is a good thing to add, even on a fill plug if that is all you have, i.e. no drain plug.

A magnetic fill plug on your diff, no excuse not to do it, easy peasy, and it is effective in pulling out metal wear bits. Add one today!

have fun!

evil_goat

Would the tool blow compressed air in the brake system? Based on an online manual, it seems that the tool somehow uses compressed air to make a vacuum.