Let’s talk about maintenance.
I understand it’s a little overkill but this is the routine maintenance schedule I follow for my vehicle:
Every 5K - Engine oil and filter change, tire rotation, grease all the fittings, inspect everything.
Every 25K - Front, center, and rear differential services, clean and oil K&N air filter, and replace cabin air filter.
Every 50K - Trans service, power steering flush, spark plugs, coolant flush.
Every 2 years - brake fluid flush.
I recently rolled 100,000 so I this week I went through and did everything listed above. I’ll get into some of the details, hopefully others can find the info useful, but also so I have everything in 1 spot to reference back to. I feel like I spend time tracking down same info over and over every time I need it.
Brake fluid:
Did you know the generally accepted lifespan of brake fluid under normal operating conditions is 2-3 years?
Let’s starting with the basics: The brake system is hydraulic system, hydraulics work on the principal that because fluids can not be compressed is very effective and transferring and applying massive amounts of pressure.
On the simplest level you apply pressure to the brake pedal, that pressure is increased and then a lot of hydraulic pressure goes through the brake lines to the pistons in the caliper, the pistons then squeeze the pads against the rotor causing huge amounts of friction, the friction causes the vehicle to slow down.
A by product of friction is heat, and a lot of the heat gets transferred back to the fluid. Brake fluid has a pretty high boiling point but track use and/or abuse can cause it to boil. When the fluid starts to boil air bubbles show up, and while fluid isn’t compressible, air absolutely is. When the fluid boils the pressure you apply to the pedal is used to compress the air instead of transferring pressure to the fluid so it can apply the brakes. The result is the brake pedal dropping to the floor while minimal braking is actually happening.
The brake system has a cap but it’s not sealed system. As the pads wear the pistons sit further and further out, the fluid in the reservoir takes up that extra system volume as the pads wear. Because it’s not a sealed system it’s susceptible to moisture and condensation. Moisture in the brake system can rust out components from the inside which can result in catastrophic failure with no visual warning signs leading up to it and it lowers the boiling point of the fluid. To combat that, brake fluid is designed to be hygroscopic, meaning it absorbs moisture. There is only so much moisture it can absorb before the fluid is considered saturated, as it absorbs moisture it lowers the boiling point further and further and it gets significantly worse once it reaches its saturation point. This is where the service life comes from.
Flushing out your brake fluid is pretty simple but it is a safety system so caution must be taken and double check your work. I always use 2 big bottles of fluid for the flush and I note the fluid level when I start and set it to the same level when I finish. If it’s midway on the scale and you fill it, when you do the brakes and reset the pistons to the fully retracted position you will overflow the reservoir.
Start with the reservoir. Flushing the fluid out of the brake lines with old fluid from the reservoir is not really beneficial. Take the cap off the reservoir and suck as much fluid out as you can - even a cheap turkey baster will work. Suck the reservoir down as far as you can and then fill it to almost the top with fresh fluid.
The shortest path is the path with the least resistance so I start at the left front. Open the bleeder and stick a piece of vacuum line on the nipple to direct the fluid into a container, with the cap off the reservoir it will have a pretty quick consistent drip. (Personally I use a mighty vac with a fluid catch and apply a little bit of suction to the bleeder just to speed the process up over letting it gravity bleed). Keep topping off the reservoir the level drops. I use an entire big bottle on this step, this ensures the reservoir is fresh clean fluid for flushing the brake lines with. Close the bleeder, your done with the reservoir and the first wheel.
From there one at a time open a bleeder and flush about 1/4 of a bottle through the remaining 3 bleeders leaving you a bit for if you need to top off the fluid back to where you started when you’re done.
You will see a difference in color with old fluid to new fluid.
It’s important to note that the bleeder screws are just blocking or unblocking a fluid passage, they are more or less small hollow 10mm bolts. They don’t carry a load, they aren’t attaching anything, don’t go crazy tightening them, they don’t need much.
Brake fluid will eat paint if it’s left to sit on a painted surface so when you’re finished make sure to clean up. A lot of people think brake clean/brake parts cleaner is the way to go, it’s not. Because the fluid is hygroscopic you literally rinse it right off with water, it will remove it completely and immediately by hosing it off or hitting it with water from a spray bottle. Brake clean smells, it’s highly flammable, it’s more expensive, and it doesn’t clean up brake fluid as well as plain water does.
Now the 5th gens are a bit different than most in the sense that they use an accumulator (basically because the 5th gen is an outdated dinosaur of a vehicle). Because of the accumulator system after flushing the system like this you will get ABS and traction control warning lights in the dash briefly once you start it up and apply the brakes to make sure they hold pressure. It with trip a fault in ABS system for low pressure on the accumulator. You can clear it with any scan tool, code reader, or mobile app that can read the ABS system.
Differentials:
The process is the same on each of the 3 diffs. Pull the fill plug first (you don’t want to drain it then find out you can’t remove the fill plug and now it has to be towed) and then drain plug. When the fluid is done draining put a new crush washer on the drain plug and reinstall it. Through the fill hole add fluid until it drips out of the hole and it’s filled. Replace the crush washer on the fill plug and put it back in. Doing the 3 diffs you’ll need one of the big copper crush washers, 3 of the rounded silver crush washers, and 2 of the flat silver crush washers - your local dealer should stock them. Note that even if the fill and drain look the same if one of them is magnetic it goes in the lower hole, the drain hole. 6 qts of fluid total will get all 3 diffs done with a little left over incase you spill some. I use Mobile 1 or Valvoline Synpower - whatever I find in stock locally but either way, a good quality synthetic 75W-90 gear oil with GL-5 certification on back is what you want.
Transmission:
There are 3 plugs (drain, check, and fill) and you want to make sure the transmission is fully cold when you start the process. Pull the fill plug, pull the check plug, then the drain plug (in that order, again you don’t want to drain it first then find out the check or fill plug won’t come out or it’s stripped or whatever). After it drains put the drain plug back in with a fresh crush washer. Put the check plug back in with the old drain crush washer and use a fluid pump to dump 5 qts of Toyota WS fluid in the fill hole and put the fill plug back in. Start it cold, shift through park, reverse, neutral, drive, then pack up through the gears to park and repeat a handful of times, just a couple seconds in each to help circulate fluid. Then let it idle in park and monitor the trans temp (scan tool or something like OBD Fusion app with the Toyota enhanced diagnostics and a Carista dongle). When trans temp reaches 105-110 degrees pull the check plug back out while its idling and let the excess drain out the check hole. Once it slows to a drip put the check plug back in with a new crush washer and you’re done. Simple drain and fill. The fill plug has a reusable rubber o-ring. The check plug is the 5mm hex one on the pan, “CHECK” is actually stamped into the head of the bolt. I believe the recommended interval is 60K for heavy load usage, and I don’t thing they recommend a fluid change for normal usage. It’s not a full system flush, the system as a whole takes 11.3qts if everything is dry and all the fluid is out of the torque converter. With a drain and fill you’ll get 4-4.5 qts of fresh fluid in it. Don’t worry about pulling the pan to change the “filter”, it’s a just a metal screen.
