lobuxracer

iTrader: (2)

For those who haven't seen this, you'll be surprised. The parking brake system on the late model IS cars (including the IS500) uses the rear caliper to squeeze the disc and hold the car, unlike our separate drum brake (and the GS F's drum brake). Why is this a big deal? I had a 1991 MR2 SC that used the rear caliper as a parking brake. If the pads are moderately warm (or worse, hot) they will transfer pad material to the disc in the shape of the pad, and it causes high spots which make the rear brakes vibrate (shudder) routinely. Toyota/Lexus went away from this with the 1993 Supra and used the same setup we have on our F cars because they knew anyone tracking the car would get their rear brake pads welded to the rotors if they used the parking brake after a lapping session.

I am truly stunned Lexus did not keep the separate drum system for the current IS cars. It makes tracking them even more difficult because you absolutely should disable the automatic function to avoid having rear brake problems at a track day.

Just one more reason to love our IS F - they really did make sure you could safely track the car without having issues by design.

Jwconeil

Is the Ebrake auto or do you have to apply it? I’ve never personally used mine.

lobuxracer

iTrader: (2)

The parking brake (it's not an ebrake) is manually activated on our cars, but automatically applied on the late model GS and IS cars. You can turn it off, but you have to make a choice to do that by unlinking it from the P setting on the transmission. In the GS F this is a separate switch. In the IS it's not quite as simple.

BMGS

iTrader: (1)

It's the same on the NX, as I found out when doing the rear brakes. Luckily you can unwind the motor using a 9v battery during brake jobs.

M4rk

Stop car. Neutral. Parking brake. Park. Shut off engine.

- since my first car

Nikeboi09

Every single time!!!!! lol

JT2MA71

iTrader: (7)

Same! Most important when parking at an incline

Quadrphnia

Very interesting info. I simply adore the brakes on this car - even with my StopTech pads which operate at about 80% efficiency vs OEM. This is the first car I have ever owned with this caliber/caliper (stupidass pun) of braking and it inspires so much trust in the vehicle.

Defratos

So for me to understand our parking brake uses all 4 calpiers when parking brake is engaged? please help me understand in layman terms

M4rk

No. It is a manually-operated, purely mechanical mechanism inside the rear rotors - much like old drum brakes. It engages the rears only. Here is an example visual of how it all comes together (not from an ISF):



Engaging the parking brake expands the shoes, which contact the inside drum portion of the brake rotor.

mk416

Gonna start doing this!

Defratos

Ok thanks for the explanation, never knew that, always thought it engaged the rear calipers

lobuxracer

iTrader: (2)

That's part of why I started this thread. While the drum brake offers it's own PITA to adjust and maintain, once you have done it and experienced a 4 click parking brake, you'll never go back. They're always horribly adjusted from the factory. Mine wouldn't even hold on my very slight inclined driveway until I adjusted the shoes properly and tightened the cable just a little bit. Now it holds even on the very steep part of my driveway (circular drive). And if you love your parking pawls in your gearbox, you really want to apply the parking brake when you park. Fixing broken pawls is no fun and very expensive.

Defratos

I've always kept my parking brake disengaged (since I nearly always park on flat surfaces).

Since my car has been in long term storage over the past 3~4 years (in the UK) it sits for 1 year intervals and I always kept the parking brake disengaged (because its on a flat surface).

Mine seems to hold reasonably well from memory on inclines so I haven't adjusted it from factory (so far)