Brake oil

[jackcramerr]

How often do you guys change brake oil? 

Last I changed maybe was nearing 2 years ago with Page dot 5.1. Is it time now?

 

Also what about air filter?

 

[NemesisUK]

Brake fluid is usually changed every 2 years

Air filter can be anything up to 4 years but for the cost I would change annually 

[Rebecca]

The 250 requires a brake fluid change every 2 years.

As for the air filter, mine is replaced every year at full service. 

[johnatg]

If you use Dot 5.1 brake fluid, you certainly need to replace it every two years. Lexus specify Dot 3 fluid and if you use that or Dot 4 I personally think it is overkill to replace it at 2 year intervals - I consider it perfectly OK to do the change at up to 4 year intervals - I have always done mine (in all the cars I service) at 3+ year intervals with no ill effects - there's nothing different about Lexus brake systems to change that view, at least in the UK climate. Garages often don't bother to change brake fluid unless you ask them specifically, even when it's on the service schedule.

Brake fluid (incidentally, don't call it 'oil' - no-one in UK does and it's not oil - it's miscible with water for one thing) comes in 4 flavours - Dot 3, Dot 4, Dot 5.1 and Dot 5.

Dot 3, 4 and 5.1 have increasing boiling points as you do along the range but also increasing hygroscopic properties - they absorb water which is why they need changing. The absorbed water reduces the boiling point of the fluid. So Dot 5.1 has the highest initial boiling point but absorbs the most water. As the chance of boiling your brake fluid of whichever type in an IS250 in the UK is vanishingly small, I use Dot 4. Actually I don't really understand why Dot 3 and Dot 4 are sold alongside each other - they are, to all intents and purposes, interchangeable. Dot 5.1 is very hygroscopic and I would avoid it for that reason - its use is really only justified in race and rally situations.

Dot 3, Dot 4 and Dot 5.1 fluids are Glycol Ether based and are fully compatible, except for provisos above. Dot 5, however is a completely different kettle of fish and is Silicone based. It has the advantage of high boiling point and is completely immiscible with water. Apparently however it is slightly compressible and that leads to a soft feeling brake pedal. Its use is really restricted to some specialised vehicles such as amphibious ones, some military vehicles and some motorcycles. It is also used in show cars which rarely turn a wheel and where the brake fluid is almost never changed.

A tip re changing brake fluid - if you keep the end of the tube leading from the bleed nipple to the waste collection jar above the level of the nipple, you don't need to immerse the tube in the waste fluid and you don't need to worry about tightening the nipple whilst keeping the brake pedal depressed. You can do the pumping of the brake pedal then saunter back to the brake and tighten the nipple - any bubbles go upwards in the tube rather than going back into the brake caliper. One man bleeding with no special kit! I put the waste collection jar on the second step of a step stool - be careful it doesn't fall off though!

Lexus specify some complicated procedure which involves using the Intelligent Tester to change brake fluid - this seems to be something to do with bleeding the Brake Actuator. But just doing it in the old fashioned way seems to work OK - at least it bleeds out quite a lot of old fluid.

Air filter - Lexus specify every 40K miles - I do it at 2 year intervals (much less than 40K miles).

[jackcramerr]

I had used 5.1 last time. And bought 5.1 just now, again....

Should have kept it at 3..

Last year I checked air filter it looked clean so wondered why anyone would change it if it never gets dirty.

[is200 Newbie]

I have used Dot 4 and looking back its been around a 2 year replacement. I fitted a K&N oiled filter when I bought the last car (5 years ago) but having looked at the current prices at around £50 each I think I will stick to the paper ones for the time being as I will not get the cost back if replacing it with an oiled one anymore. I am sure the last one I fitted cost me around £20 which was well worth the money - cant believe the price increase on these ...!

[Rebecca]

4 hours ago, jackcramerr said:

I had used 5.1 last time. And bought 5.1 just now, again....

Should have kept it at 3..

Last year I checked air filter it looked clean so wondered why anyone would change it if it never gets dirty.

It may look clean but don't assume it is. 

You would be surprised at how quickly an air filter can clog up with invisible dirt robbing you of valuable air.

Air filters cost peanuts and are easy to replace (even I can do it)

Well worth changing every year I say.

[Texas]

If you wanna 're-fresh' your air filter at 6 months say, you can use an air line and carefully blast the filter carefully in the reverse direction of its normal air flow to remove any loose build up of contaminants. Try not to breathe in any of this Krap obviously!

paul m.

[jaaniic]

On 3/9/2018 at 5:47 PM, johnatg said:

Lexus specify Dot 3 fluid.

Dot 5.1 is very hygroscopic and I would avoid it for that reason - its use is really only justified in race and rally situations.

There is only Dot 5.1 available at lexuspartsdirect. I guess that's what they use and recommend for all models now?

On 3/9/2018 at 5:47 PM, johnatg said:

Lexus specify some complicated procedure which involves using the Intelligent Tester to change brake fluid - this seems to be something to do with bleeding the Brake Actuator.

Don't know what to do. Trust this with 3rd party service or take it to Lexus? Cannot do it myself unfortunately.

[johnatg]

If you are not doing the job yourself just trust the garage to supply their dot3/4 stock. There isn't really anything special about brake fluid.

A competent garage should be able to change fluid and/or bleed the brakes.

[H3XME]

9 minutes ago, johnatg said:

There isn't really anything special about brake fluid.

Oh there is, boiling points differ & low temp viscosity is different between DOT 3,4,5,5.1 etc. This is why you wouldn't use a DOT 3 or 4 on a race car as the brakes get way hotter. Similar to road cars in winter, you'd want DOT 5.1 due to its low temp viscosity which is better for stability of ABS. 

[johnatg]

5 minutes ago, H3XME said:

Oh there is, boiling points differ & low temp viscosity is different between DOT 3,4,5,5.1 etc. This is why you wouldn't use a DOT 3 or 4 on a race car as the brakes get way hotter. Similar to road cars in winter, you'd want DOT 5.1 due to its low temp viscosity which is better for stability of ABS. 

I meant between brands - and it really doesn't matter if you use dot3 or  dot4 in a road car (although low viscosity versions are preferable with abs or non-brake hydraulic systems)

Dot 5.1 needs changing more often.