Rear Tire Leaking Oil - Heard bad grinding noises before tire oil leak - The leak was brake oil not diff oil - SOLVED (1 Viewer)

[BnvS]

Ok so I have a issue at hand.

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Solved - Turned out to be a bad Caliper piston that was rubbing on the rotor. I replaced the rear rotors, pads on both wheels, did a little bit of brake bleeding. That fixed the problem. I did put in a brake noise shim this time so I know if my brakes pads are about to go. Saving me the problem of replacing the rotors.
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Symptoms while it happened -

Initial symptoms - Grinding noise from rear area (thinking break pads maybe bearings):

I was noticing that I had some grinding noise coming from the rear end. I thought it was some brake noise and that the rear brakes pads needed replacing. But then I heard the noise all the time even when not braking so I thought the rear bearings may need replacing as well. I do enough off roading in muddy GA that my car get quiet dirty. So thought the rear bearings are also gone. Thinking I'll have to change soon them I kept on driving no more than 5-7 miles around the house. Also I have not checked on the differential plug if its clogged or not.

Today's symptoms - not so good grinding noise, hesitation, bang then Rear tire oil leak (all within a 1 min or so)

However today while driving slowly 5-10 mph (btw all this happened within 1 min). I suddenly felt as if I got hit from the back..like a thud but nothing hit me from the rear.. so I checked if my transmission was going into another gear. But nothing so I drove a little bit further.. then heard a bad grinding noise and a little bit more hesitation, felt like something is grabbing the wheel until I heard a bang and as I mentioned the grinding sound. Obviously this was not good so I stopped and checked thinking its my transmission. However, I found the rear drivers side tire leaking oil. I managed to get home without any more grinding, break grabbing/hesitation, banging or bad noises. While driving back I got my brake light on. I think I am leaking break fluid (kinda confirmed by checking the brake reservoir.

Searched Mud I think its rear axle seal leak, but wouldn't that leak differential oil? and not brake oil? I think its brake oil b/c I remember diff oil being thicker.

What do you gentlemen/Ladies think? diff oil leak? or something else altogether?

 

[GTV]

I think if you took the wheel off you'd find your answer.

 

[hoser]

Take a white piece of paper or napkin and get a sample of the fluid. If it is dark and stinks, it is diff fluid. Drain the diff, check for metal bits and pieces. Also, you should stop driving it.

 

[dogdaysindurham]

My guess is that your rear brake pistons pushed through the remainder of your brake pad. The grinding may have been the wear indicators in the pads.

 

[BnvS]

Yeah I'll open this up tomorrow morning and hopefully find out problem. Hope its just the brake cylinder that spring a leak. But the grinding noise and the binding makes me think it could me more than just that. Hopefully its all repairable without to much fanfare.

 

[Malleus]

My guess is that your rear brake pistons pushed through the remainder of your brake pad. The grinding may have been the wear indicators in the pads.

Same thing happened to my LX570. I was very unhappy to realize the pistons could move so far that they could pop out of the calipers. Really poor design. Cost me a new disc and a new caliper.

 

[excessive]

My guess is rear axle seal

 

[Marshmallow]

If it’s brake fluid the pop sound is probably the brake pad metal backer popping between the caliper bracket and the disc with the caliper piston now grinding on the disc. I had a sticky piston that wore the drivers rear inside pad down to nothing and it made a pretty good clunk as it escaped (outside pad maybe lost 1/8” to wear in the same time). You’ll have to pull the disc (just two extra bolts for the caliper bracket and it should slide off) to find a missing inside pad backer.

 

[BnvS]

So today I took the rear wheel off. The rear oil leak looks very much like break oil. Almost clear and slightly smells like synthetic oil. I am pretty sure its brake fluid. Obviously the brake caliper was wet.

I didn't open it all b/c it was daam hot 90+ and I was dripping sweat like a wet rag. I didn't see the inner brake pad at all. Only see the rear piston
kinda messed up all grinded up as you see in the pics. I'll open it up in full in the evening when it cools down.

Here's what I got for now.

 

[Trunk Monkey]

As mentioned, new caliper, new rotor (and new pads), bleed system. Good reminder to check pads every now and then.

 

[Mike NXP]

So today I took the rear wheel off. The rear oil leak looks very much like break oil. Almost clear and slightly smells like synthetic oil. I am pretty sure its brake fluid. Obviously the brake caliper was wet.

I didn't open it all b/c it was daam hot 90+ and I was dripping sweat like a wet rag. I didn't see the inner brake pad at all. Only see the rear piston
kinda messed up all grinded up as you see in the pics. I'll open it up in full in the evening when it cools down.

Here's what I got for now.

View attachment 3407505

View attachment 3407494View attachment 3407495

Pop the hood and make sure your fluid is topped off if you're still driving it.

 

[Marshmallow]

As mentioned, new caliper, new rotor (and new pads), bleed system. Good reminder to check pads every now and then.

Yeah, that is almost what mine looked like. You’ll find the brake pad rattling around between the disc and the shield (or in my case two of them since I didn’t fix the sticky caliper the first time!). The work is pretty straight forward and easy, no more than a couple of hours once you have parts. Replace rotors and pads on both sides.

 

[BnvS]

So here are the pics of the caliper piston. It is in pretty bad shape as you can see in the pic. Ooh the inner brake pad that was no where to be found was inside the drum/rotor.

I am finding Piston kits that provides the 48mm piston, rubber cover, seal and all the hardware and rubber boots plus hardware - FRENKIT 748345 coming for $35

or should I do that or replace the whole caliper assembly.

Anyone use non OEM components for this stuff that they think are good and recommend?

 

[bj70bc]

wow

 

[kwon-offroad]

Drive it 'til the wheels fall off...literally.

 

[Dirt J]

I've read on here good things about certain Napa calipers. Paging @2001LC -- I think he posted it.

I'm assuming the disc rotors gouged up too and will need to be replaced...

 

[BnvS]

Update....on this..I took the caliper out cleaned it. Looked at the caliper cylinder. I looked in decent shape. So I got the caliper piston from Rockauto. I would have ordered OEM piston. But Its not available at least in the SE from the Toyota Dealerships..And they didn't know when they would get it in either. Which is why I went with Rockauto's solution. I could not get the OEM rubber kit either...so ordered that from Amazon

Here are the part numbers for my stuff I got


Rear Piston - Carlson 7113
Rear Caliper Rubber seal kit from Febest - 04479-60250 / 447960250 - Cylinder Kit For Toyota

I put it together and here's what I got so far. If the SE rains let up I'll install it and see if it works.

How to fit the boot -
Btw putting in the rubber boot was tricky if you haven't done it before. After looking at some videos online. I found the best way is to put the boot on the caliper is the following -

Pre-grease your components - Square rubber o-ring, piston, rubber boot ends

I assume you have put in the square rubber o-ring into the cylinder already and are using the Lithium soap base grease. I am 99% sure Silicone grease (aka dielectric grease) can be used here as well) in place of the Lithium soap grease. As long as the grease is SAFE for Rubber components I think you should be good.

Prefit (to see how the boot it sits in the caliper cylinder groove) - First just fit the boot on by itself on the caliper cylinder to see how the lower "boot lip" fits the cylinder groove. You could clearly see how the boot fits into this groove and the way it sits. Now you know how it sits in the groove, Remove it and do the next step below.

Final fit - From the top fit the boot on the piston, Then bring it all down till the end of the piston edge. Let the "lower boot lip" that is supposed to sit on the caliper cylinder groove hang over the piston bottom edge by about 1 cm or so. Fit the boot lip first and ensure it fits the groove like you see it fit in the Prefit session. You should see it fit the groove. The back part will need a little bit of pressing using a Philips screwdriver (do not puncher the boot obviously). Once its site the groove push the caliper down and it will fit perfectly. Make sure the "upper boot lip" fits into the upper piston groove as well. See pic below.. on what I mean...

Btw if you piston goes in and your boot does not fit properly then use compressed air to take the piston out again. Be careful and not have your hand to catch the piston. It comes out with some force. I used some paper to stop it.

Close up of the Caliper piston boot

 

[Dirt J]

Good job rebuilding the caliper. My fronts need this.

Did the rotor end up being trashed?

 

[BnvS]

Good job rebuilding the caliper. My fronts need this.

Did the rotor end up being trashed?

Yeah the rotor was trashed obviously.

What I can't believe is why I didn't have any noise shims in the old brake pad. I am assuming this was factory brakes. So they could have put in a noise shim so I didn't have to ruin my caliper piston and rotor. And have me worried my differential going bad.

Oh well you live and learn.

 

[BnvS]

Ok got all the work compleated it was indeed only the caliper piston that was the problem. I replaced that, the rotors and pads on both rear wheels. Everything works now as expected. I was expecting to do a lot of brake bleeding but I didn't need to do too much. Testing everything today. It works great..

Thanks for everyone for your input.