2007 RAV4 brakes - fixed for sure?

Banty

Hello, all.

I have a 2007 RAV4 that I bought last July. The brakes felt a little soft on the test drive; I asked them to look into that and make adjustments, and after that it seemed fine.

Two weeks ago I started getting a grinding sound when I pushed the brakes hard enough (I'm generally really easy on brakes), and brought it in to a foreign car specialist. My front brake pads were worn, on one side especially. The rotors were bad, too. The back brakes were OK for a few more months, he said - I said I'd like to have all four brakes done for a fresh start.

When I picked up the car, he was bleeding the brakes a second time, saying that they felt to squishy to him when he took it for a test drive. I took it out, and to me it felt as good as it did before. He said it was probably a characteristic of the car.

The brakes seem fine to me, but I started reading about brakes and problems, and one thing caught my eye - that when waiting at a red light, if the brakes start to drop after about 20 seconds, that's a sign of a bad master cylinder. My car was doing that in the past month. Now, after the repairs, it does not to that anymore. But the mechanic did not replace the master cylinder (I didn't think to tell him about that).

If it doesn't do that anymore, is it fixed, and the problem was related to the pads, or to low brake fluid as that drops when the pads wear? Or should I change out the master cylinder just to be sure?

Thanks.

Tester

Anytime a brake pedal slowly sinks to the floor, no matter how long you sit at a stop means there's a problem with the brake master cylinder. Brake/clutch master cylinders can be effected by temperature. So if you notice this sinking brake pedal when the temperature changes, It points to a brake master cylinder leaking internally.

Tester

Banty

Thanks, Tester.

So I think you're saying, I should replace the master cylinder anyway, although I haven't had the pedal drop since the brake work was done, because there may be other factors, like temperature, which may be masking a problem?

the same mountainbike

It is possible since the brakes were totally worn out that the reservoir had dropped too low and there was air in the system, and now that the system has been well bled there's no problem. Since you stated that you're easy on the brakes, it's a possibility. Most folks would jave pumped them and felt them get harder as the air compressed. How things feel to a driver can be tough to convey over the internet.

Be aware of the possibility that Tester suggests, and if you start to have a problem with the pedal sinking again the MC is definitely the place to start looking.

Banty

Update: Brakes are still acting OK, but I'm getting the MC replaced anyway. The mechanic said the reservoir was not particularly low when he did the earlier brake work, and frankly, I need it done for peace of mind. Maybe it's marginally bad.

It'll get done as part of the 60,000 mile checkup.

the same mountainbike

Sometimes it is worth the money just to sleep better.
Sincere best.

circuitsmith

I could be the MC is a little iffy and when the brake work was done new brake fluid was introduced into the system, which rejuvenated the MC.
5-6 years is a little young for a master cylinder to go.
If I had any doubts about a master cylinder I would change it too

If you get the brake fluid replaced every 3 years the various brake components (besides the pads and rotors) will last much longer.
This is especially important on a vehicle with ABS.

Banty

Thanks, circuitsmith - how would the master cylinder be rejuvenated by new brake fluid? (curious..)

Work is getting done tomorrow, by the way - thanks, all.

circuitsmith

Clean fluid free of moisture might help the seals work better for awhile.
They're mysterious little fellows...

Banty

Update: So, I got the MC replaced (and tranny fluid changed, and 60,000 mile checkup). Brakes seem a bit better - surer. Or it could be my imagination. At any rate, it's done and I don't have to worry if I have a marginal master cylinder. I'd rather have a car that can't go, than can't stop.

Cheers,
Banty

Banty

Well, the beat goes on - looks like the mechanic put the wrong transmission fluid in. He was stating to me with confidence that he uses only Toyota products, "T4". I went home, looked it up, and that's the wrong stuff, it's supposed to be "WS".

I called up the area Toyota dealer the next day, they said to bring it right in for a flush and to replace the fluid. $$$$. They said they weren't sure if there was damage or not. I did not notice any shifting issues; I only had driven about 25-30 miles in the interim.

Do I have a new issue?

galant

No damage, WS is full synthetic and newer version. Maybe a drain and refill X 2 to 3 would suffice. YOu should be able to do it yourself. With the cost of the ATF, your bill is going to be high. You will probably need 8-10 qts of fluid at the tune of $6+ per qt.

Banty

Thanks, galant. The dealer did the flush; they used 16 quarts according to the bill.

How many quarts would a single drain and refill be? (If it were done right the first time..)

galant

If it is the 4 cylinder it is 3.7 (4) qts for the drain and refill. It is 5-6 qts for the pan drop and filter/gasket change. You did the right thing, even though maybe more $$, in the end a transmission costs way more.

The interesting thing is the same transmission in the 05 Models call for Type IV ATF, then Toyota or whoever makes the transmissions for them, upgraded the fluid to WS. When I buy my ATF from the dealer, I have to take a picture of my dipstick with me, otherwise the counter person thinks I am being stupid and saving pennies buying the wrong ATF.

Banty

Yes, I read somewhere else (RAV4World, I think) that they started with the '06 with WS. Apparently some RAV4 models have no dipstick to make sure only a dealer changes the fluid.

Banty

Belated upate - the mechanic, when I asked him the following Monday what ATF he used, he confidently stated "WS". Probably, he's right and mis-spoke (or I mis-heard) the Friday before.

1500 miles now, no tranny issue or any other new problems.