Buddiiee

(Whoops. This title was meant to read 250 and 350 rear brakes)

Ok, I was reading a little on the rear calipers of the 250 seizing up on people. After a little research I came up with the info that this failure was on the 250's and not the 350's. Now that I rebuilt my rear brakes I've NO clue who said that lol. They're very similar brakes set ups.

My driver's side rear was locked tighter than a fistful of superglue. Took 20 minutes with my old reliable 50/50 mix of ATF and tranny fluid in a squirt bottle and a rubber mallet to get that ****er off. Once off I noticed the torn boot that seals up the relationship between the caliper slide pin and it's corresponding hole on the caliper. WTF was this last owner doing to this thing?? It was only 6 years old. Oh, that's right, it was a chick. Figures. I've owned cars for 10 years and never ripped a thing on them. Can't figure out some car owners. At any rate, I cleaned everything out as best I could, reinstalled some new replacement boots I purchased, and greased it up with silglyde. It's actually a pretty neat set up. Slides really nice.

At any rate I think I know why these things are locking up, and I know how to prevent this in the future for guys like me, that have zero interest in changing cars every 2 years. If you're like me and you like to keep your car for many years here's a suggestion. The boot on the slide pin that is stuck to the caliper bracket, that you slide the caliper off of to remove it was very difficult to reinstall the RIGHT way when I did the replacement. It was all too easy to just stick it over the lip on one side of the two surfaces and just throw the entire caliper back on and go, but I didn't. I maintained until both sides were sealed. It was not easy. I can see why many mechanics that are rushing against the clock rush this procedure & skip sealing the boot completely. This allows salt water (if you're up north) to get in there and wash your lubricant away. And I don't care WHAT grease you use, constant salt water will destroy any lube on a car up north in short order. And even if it doesn't wash the lube away it corrodes the metal inside, and then that rust just dilutes the grease until it's completely ineffective. From seeing this I actually can't believe ALL our rear brakes aren't seized here in the North.

I'm betting this happens because unlike normal old school calipers, to replace the pads you have to pretty much remove everything to make that happen, kind of forcing you to rebuild everything in a way, and to loosen things up a bit. On these new style calipers, all you gotta do is remove some pins, slide out the old pads, throw in the new ones and you're done. The caliper never gets to come off to get inspected and regreased. ESPECIALLY by non car guys who have no idea what they're doing. And even if you know what you're doing, I can see the upper removable pin coming out, then you rotating this caliper up, dislodging that boot, then rotating it back down and either ripping or not noticing you've dislodged this boot and finishing the job, without ever having to inspect that boots replacement. I bet 500$ this is why these things are not sealed or just totally ripped like mine was.


If I were you, I'd do this right now in the summer while it's easy - buy some new slide pins and boots. Yank your caliper off. Heat that probably seized in slide pin, install the new one, clean the CRAP out of that hole, put the new boot and grease in, and make SURE both sides are wrapped around both lips, and not bound up anywhere. I've found that when properly cleaned and lubed, without overlubing, and when both boots are actually present the caliper slides really nicely, and will slide back off of the rotor on it's own accord, rather than just sitting there on the rotor, hoping the rotor's minute amount of runout will bump the pads off of the surface by itself. Once I got this entire system running the way it should, I realized I really like it. It's a lot nicer and smoother than the other setups I've owned.
To go one step further for the winter, I'm having all my brake pad retaining pins and caliper slide pins coated in Robar's NP3 electroless nickle coating, so they'll NEVER rust again. I want to put this stuff back together one more time and not have to screw with it for years to come

(if you guys need pictures of what I'm talking about let me know. I'm going back in to check pin diameter before sending my pins off for coating)

DennisMik

I learned about those slide pins years ago. Nothing has changed - they are still becoming corroded and binding. While causing the brake to lock up is the severest manifestation of the problem, another and I think more common indication of slide pin problems are that one of the brake pads wears out and the other one looks good.

As you well know, a rubber boot isn't put on something for decoration. A torn boot is saying "Here's a problem." When I encounter slide pins that are binding, I go to my local parts store and get a pin replacement kit. I am not comfortable with greasing and re-using them.

The only thing you are incorrect about is that the problem only happens up north. It happens down here in the south, too. Just not a fast. I guess roadkill guts are also corrosive to the brake parts.

XSV

iTrader: (1)

Both my IS250 rear and my IS350 BBK both had rear caliper seizing problems. One of the rear IS350 calipers had slider pin seize and rust and rusted in the piston well and the piston was rusty and pitted. I am in the South as well.

Buddiiee

Wow! Then how does the rest of your NON grease coated car parts stay so pristine down there? lol.

DennisMik

Our good looks and Southern charm

primavera

I just serviced my rear calipers yesterday, noticed for some time the rear left rotor didn't look too good and was generating lot of sizzling heat.
Anyway, pushing the piston in and removing the caliper was super easy, removing the pins was the biggest pita, they were stuck frozen.
Lots of rust penetrant PB Blaster and solid hammering (omfg)!!! finally got them out!!. Cleaned them all up nicely and they looked as good as new.
Made a trip to Napa and got a tube of Syl-Glyde.
Inspected and cleaned all rubber boots, packed em up with fresh Syl-Glyde, cleaned rotors then put everything back together.
Less then 2 hours of work on my driveway, they seem to be working fine for now.
Those dreaded rear calipers seem to be a problem on older IS and GS cars.
Apparently Lexus redesigned calipers for the latest IS and GS cars, does anyone know if it's an easy swap to 2nd Gen IS?

MikeFig82

iTrader: (13)

Sil-Glyde is what I used about a year ago. I may just pull the rears off again to re lube them up. I want to see if it really holds up to the heat. I did use the permatex crap ceramic it dried up almost within a month.

Tungstn-IS

I'm confused here. The pins in the picture you posted are not what causes the problem, they simply just hold the pads in place. If you were able to easily seperate and remove the caliper, then the pin that is prone to seizing and screwing everything up was not seized.

This is the pin that seizes up, preventing the caliper from sliding or coming apart, causing it to wear out only one pad and not allowing you to install new pads.

primavera

In my case those pins were the problem, they had surface rust and oxidation on them, hence forcing the pads to be stuck in skewed position and only grabbing the rotors partially. Pads were not moving freely even though the guide pins still had little bit of grease and were not seized. Once I cleaned those pins and re-greased the boots, everything worked as it should.

I forgot to take pictures, but I'll use the one I found online.
As you can see from the picture, 2 pins go through the holes in pads, if the pins get rusty the pads get stuck in one position and stop moving from side to side.



You may not have the same problem in Texas, I live in Canada and we get snow and salt for 6 months lol
Hope that helps.

Tungstn-IS

I know what you mean, but that is not what they are talking about in this thread.