I am doing an 04 tundra brake replacement on my 97 4runner. I got all the parts in: new rotors, pads, lines, calipers, brake cleaner, brake fluid, and caliper paint. I got a question about the fluid? I've got weaver synthetic DOT3 fluid http://shop.advanceautoparts.com/web...%7CGRP2008____ and was wandering if this was bad to have synthetic fluid or if it matters or not. I got it because it was buy one get one free same with the brake cleaner at advanced auto. Any help would be great. Also while be doing lots of pics and video of this swap to help others out who wish to do this conversion. Thanks in advance

 

I have the FSM for my '98 which should be the same as yours. Manual states in Brake section "fluid:SAEJ1703 or FMVSS No.116 DOT3"

I'm thinkin if you use any DOT3 fluid you should be ok. I would not recommend mixing synthetic and non-synthetic oils. I'm not Toyota master mechanic so just keep watching the posts for more input. Good luck

 

i agree with Ritzy4Runner that synthetic brake fluid is not supposed to be mixed with the non-synthetic type of brake fluid. although there are synthetic brands that are silent about mixing their product with a different type of brake fluid. best way to use what you have bought is to thoroughly flush your brake system with synthetic brake fluid. that means you'll have to buy extra bottles of synthetic fluid, drain the brake fluid reservoir, and the master cylinder too.

 

Thanks! I will be completely flushing the Brake system so no mixing will occur, but still don't know if the synthetic stuff will mess something up. My father was saying that on his 91 Benz that it said not to use synthetic.

 

I've got 2 bottles of the 32oz haha little much i know. Any tips on flushing the fluid out of the Master cylinder and reservoir?

 

no, it won't mess anything.. DOT 3 is the minimum. i'm using synthetic DOT4 without any probs. currently, there's now DOT5.1, but i'm not sure if our system will be fine with this new type. drain the reservoir by buying a suction tube and a little hose.. just like a the kind a medtech uses to extract blood from your veins but somewhat bigger to accommodate the volume of brake fluid.. about the mc, disconnect the 2 brake tubes then ask someone else to pump the brake pedal.. you'll need someone's help here to ensure that the fluid doesn't spatter on the body as it will eat out the paint!!

 

Sounds good looks like no problems with the synthetic. I was told do not use DOT 5 it is silicon based and because of that messes up the rubber parts and seals of brake systems that were to use DOT 3 & 4.

 

When you're flushing, start with the furthest one out, passenger rear and flush until you see new fluid. Then work your way back. I wouldn't pull anything out of the reservoir as it can cause air to get in the system. Just bleed it, add more, continue bleeding until you see new fluid. Then do the others working closer to the master cylinder.

DOT5.1 is silicone based, it doesn't mix at all with the others. You can use synthetic or normal, just don't mix them, flush it out completely.

I use racing fluid for the race car and that made me use it for my regular cars as well. I use ATE Superblue or AP Racing. Much higher boiling point than DOT3. It's overkill, but I tow with the 4Runner so it's sometimes hard on the brakes.

 

To amplify the flushing, you need to get all the fluid out of your system. As was stated drain/remove the fluid from the resevoir, drain the fluid from your master cylinder, refill the resevoir with the new fluid, start purging your system starting with the right rear wheel.

Get yourself some 1/4" tygon tubing about 2 feet long and a container you can flush the fluid into. locate the flush/bleed port located on the inside portion of the brake assmbly. Loosen this fitting but just break it free and then snug it back. I believe it takes a 10mm wrench.

Attach the tygon to the nipple of your brake bleed fitting. If you have never done this it looks like a zerk type grease fitting without the little check ball in the nipple end. Have an assistant pump the brakes up and then tell them "HOLD". Loosen the fitting and you should get fluid squirting down the tygon tube into your container. Tighten the fitting, have them pump the brakes a few times and repeat as many times as it takes to remove the old fluid and you begin to see new fluid. A tip to new fluid arriving at your brake cylinders should be some air bubbles from removing the fluid in the resevoir. After you do 2-3 bleed cycles on a wheel, besure to check the fluid level of the resevoir, you don't want it to get so low during this procedure that you start sucking air back into the lines. It is imperative that you get all the air and old fluid out of the brake cylinders, master cylinder and brake lines. Good luck

 

Thanks for the info on the types of fluid i shouldnt have any problems with the DOT 3 because i dont do much towing. The Mud grapplers are very heavy and take a lot to slow it down but i'm sure the tundra brakes will help.

 

This helps didnt know if there was any trick to the toyota brakes. I've done lots of brake jobs on older trucks with discs and drums but wanted to make sure i wasn't over looking anything.