Brake overheating? It was a hot day, but it was traffic...

[Dubbrado 10]

Hi all,

 

Wanted to ask for some knowledge on brakes.

 

The other week I was stuck on the M6 for ages, it was a brutal day for traffic jams and 24 degree + heat.

I could see oil temp at 125-128 which **** me up a bit at the time seeing no movement in the traffic, so went through Wolverhampton, traffic still terrible, and not getting above 30 mph for some flowing air, it's still not cooling much.

In the stop start traffic suddenly I had no brakes, the pedal just pushed flat to the floor, I'm thinking this is overheating of the brakes no doubt, but I've never known it in such low speed applications on any other car?

Could this just be crap brake fluid that's boiled over or something a little more concerning?

[DriverVR6 11]

There's no way that stop start driving and braking from 30mph to 0mph will cause your brakes to get so hot as to result in having no brakes at all.

 

For it to happen you must have a serious amount of water in your brake fluid or some other defect?

 

Let me know the colour and reg of your Corrado so that if you come up behind me I'll know it's you and I'll pull over and let you go past!!

[Dox 22]

If you don't know when the fluid was last changed I'd change it asap after a full inspection of all brake lines underneath the car and caliper seals etc for leaks.

 

If you lose the pedal after changing the fluid and there are no external leaks suspect the master cylinder to be toast

 

 

I bled my DBP twice, on the right is the first flush, second on the left

Edited July 2, 2014 by Dox

[Dubbrado 10]

Haha, thought as much!

 

Tah for confirming my fears, don't fear it won't be driven until that's sorted!

[Ray1965 10]

The only time your brakes over heat is 60 laps round Cadwell park !! As for the oil temp i'm not sure if yours is a tad high?

I was in traffic with the same outside temp as you and my oil was around 94 -96.

[Dubbrado 10]

Having a think on this a bit more, my car had a new right front wheel hub for christmas MOT, could it be possible this has been fitted incorrectly and causing too much brake-rub and overheating that way?

Ray I don't know what to say about oil temp, mine normally idles at around 94-96 when cruising at say 60 on a warmish day, could I have more problems here too?

[fla 9]

If your oil was at 126 then you would feel a major blast of heat every time the fans kicked in. It might just be a faulty sensor or spade connector. I assume your fans are running properly though?

[Dubbrado 10]

Can't say I noticed the fans kicking more heat, but then again I was running some heat through the matrix while in traffic in an attempt to cool it down. The fans were working full tilt when I popped the bonnet after the brake failure. Never seen or played with any engine bay sensors before to know much more unfortunately, appreciate the help though, all things for a check list!

[g0ldf1ng3r 13]

it is possible for the oil temp sensor connector to become corroded & this can result in spurious reading on the dash - i had this issue when my VR had its work at stealth & was getting ridiculous readings

 

it should be easy to tell if you pull the connector off the sensor & check the wires are ok & the inside is not corroded

[Dubbrado 10]

it is possible for the oil temp sensor connector to become corroded & this can result in spurious reading on the dash - i had this issue when my VR had its work at stealth & was getting ridiculous readings

 

it should be easy to tell if you pull the connector off the sensor & check the wires are ok & the inside is not corroded

 

Nice one, certainly doesn't hurt to have a look.

[g0ldf1ng3r 13]

Nice one, certainly doesn't hurt to have a look.

 

glad to help & share knowledge from experiences :) good luck

[Supercharged 2]

Check the fluid and that heat shields are in place and not damaged etc...

 

I take it you were using the clutch a fair amount? I'm wondering if the clutch cylinder is leaking and the fluid level dropped.

 

Also check both brake and clutch masters from inside the car for brake fluid.

 

When was it last changed??

 

If one caliper is binding you'd smell it walking round the car and that whole wheel would be noticably hot.

 

Don't drive the car until you're sure it's fixed - maybe an internally collapsed hose or corroded line.

Edited July 3, 2014 by Supercharged

[Sean_Jaymo 0]

Oil temperatures tend to be 12-15 degrees above water temperature in normal driving, usually less than 8 degrees if on the motorway. If you're giving it some love maybe that would extend to 20-25 degrees. If your radiator fans are working correctly, the oil temperature shouldn't be much above 115c. If the water is kept to 95 or so and the oil starts to reach 120 or higher than that, you have an issue somewhere, either it is a bad temperature sensor, a bad joint on the wiring to the sensor or worse, a tired old oil cooler.

 

Just as a heads up to anyone who has replaced the sensor and cleaned up the wire and you are still getting high temperatures, if your oil cooler is the original item, get it changed before you risk it failing and causing an engine failure. They can fail from fatigue of the metal itself, resulting in leaks or failure in the oil/water matrix internally which can lead to water getting into your oil and causing all sorts of headaches.