ryanwongg

Hello all,

For anyone who has upgraded their IS250 brakes to the IS350 calipers and rotors, could you please confirm my shopping cart has all that is needed to get the project done?



Parts are from RockAuto.com and the calipers come with the hardware kit and metal pistons. Pads will be ordered elsewhere after I do a little more searching for quiet/low dust pads.

Thank you!
Ryan

Sasnuke

The front calipers look like the correct ones.
I never thought about changing the rear, so not sure about those.
From the front rotors, if your 250 is AWD, then make sure you get the AWD 350 front rotors.
What about the front backing plates? The 350 front rotors are bigger...so you either bend/trim the 250 ones, or buy the 350 ones.

ryanwongg

Thanks Sasnuke!

Regarding the rears, I read in a couple different threads you're supposed to change to 350 rear breaks if you change the front... I saw several people state it could be very dangerous if someone were to only change the front? can anyone please confirm?

Regarding your two other points, this is a RWD (sorry forgot to state that in original post) , and I plan to bend/cut the backing plate

Other than pads, these parts are all I need? thank you!

Sasnuke

Can I be honest...cutting and bending the backing plate to make the rotor fit really defeats the purpose of the backing plate.
The backing plate should be bigger than the rotor in order to provide the protection is was designed to provide in the first place.
Since your IS is RWD, it would be super easy to change the backing plates, and they are $15 CAD (that's not a typo)...so that's probably $2 USD (lol...damn exchange rate)
Removing the front wheel bearing assemblies isn't that difficult on a RWD...on the AWD, it is a little more difficult to the point people may not want to do it, especially if you don't have the right tools (the big socket for the axle nut).
Just my thoughts on the whole backing plate situation.

Never heard that about the rear brakes...at a quick glance I thought they were the same (size and construction), but never looked up the part numbers to confirm.
The reality is they are both a floating single piston caliper...if the 350's were bigger, I can't imagine it's a world of difference. I guess the question is how much more braking performance do you want. I would think the much bigger front brakes would be enough.

ryanwongg

The front backing plate will be cut as I've read it's simply a matter of cutting a small section to accommodate the caliper. I've also read it's harder to re-use the is250 rear backing plate as much more bending/cutting would be necessary to accommodate the 350 setup. Thanks for the tip! I will look into getting the rear backing plates.

I believe rear 350 rotors are slightly larger and thicker. The 250 calipers may look similar but the 350 caliper are different to accommodates the thicker rotor.

Sasnuke

Before you disassemble the front brakes, note how the backing plate extends past the rotors...should be enough to cover the rotor.
When you put the 350 rotor on, the backing plate will virtually disappear. In addition to cutting you'll have to bend it back.

The rear backing plates will be harder than the front of a RWD...or just as hard as the front of an AWD. The axle needs to be removed from the wheel bearing assembly.
The nut is a staked nut, so really you should replace the nut anytime it's unstaked. Most people reuse them though.

ryanwongg

Thank you for the detailed info! I'm leaning towards bending the rear... After further reading, I think I'd prefer to do more bending than disassembling of more parts that possibly should be replaced (staked nut). On top of that, I don't think the heat shields are as cheap as Canada... Ive been reading on average $45 per side in the U.S.

Besides the pads, I think its time to pull the trigger if my shopping cart has everything needed for install!

fivesevenn

just checked on the Lexus parts catalogue, is250 2015 axle is the same at is350 2015 fsport. (Must confirm with Vin.)
and no, you dont have to change rear pads when you change the fronts. rears will always last longer than the fronts (fsport)

Sasnuke

I believe the he was referencing change the rear brakes to the 350 ones when you're changing the 250 fronts to the 350 fronts...not the actual pads, the entire brakes (calipers, rotors, pads, etc.)

ryanwongg

I would like to point out from the screenshot in my original post, I had 2013 IS350 rear calipers, rear rotors, and front rotors.

After ordering everything in the screenshot, I've realized the IS350 rear calipers have changed after 2013 and now I'm questioning whether it would fit my 2014 IS250...

Can anyone please confirm all my parts before any painting is done?

ryanwongg

bump, can anyone please confirm?

davyjordi

I'm pretty sure that there are going to be some differences. Have you already made the purchase or are you still gathering information?

Sasnuke

Here's my 2 cents...
The parts above for the 2013 IS350 are only for 2IS.
The fact that Lexus did not carry forward the parts to 3IS either makes me believe they wouldn't fit, they wouldn't be sufficient, or there were issues with them/design.
As this would have reduced production costs, I think there is a very good reason why they didn't carry them forward. And yes, the current rear IS350 brakes look to be of a very similar design.
Additionally, since they did carry forward the front brakes, then there must not have been any issue with them

Now, whether the 2IS rear brakes will fit a 3IS physically...the only way to know is to try and fit them.
However, given that Lexus didn't even want to try and make that fitment work, I would probably stay clear of them.

ryanwongg

Unfortunately I've already made the purchase way back when I originally posted since I was under the assumption all parts were good.

Without confirmation from anyone, I'm still led to believe the rear calipers will not fit simple due to the design/bolting mechanism of the 2013 model. For this reason, I'll go ahead and order the newer year'd calipers. BTW I believe the "2013" rotors will fit fine as they are the same part numbers for the 2014+ rotors

Thank you for your responses!

Jeff Lange

iTrader: (1)

The rear suspension design on the 3IS necessitated a different knuckle design. The calipers were moved from a trailing position to a leading position. The mounting is different as is where the bleeder, etc., is placed. The late model 2IS models did have updated rear brake calipers (along with larger mounting bolts), however these also cannot be used on earlier 2IS models without swapping out the rear knuckles.

The front backing plates are cheap and relatively easy to change (if the bearing assemblies come out from the knuckle easily), so I'd recommend changing them. The rears are harder and more expensive, cutting can work well here (the rotor size difference is not as pronounced as on the front).

Make sure the rear calipers you get match the year of car you have. The ones you have in your cart look to be for an early model 2IS, I believe.

Jeff