Hi all,

 

Two mornings running in very low temperatures (-8 & -6 deg.) I was aware that the brake pedal needed excessive pressure for not a lot of retardation. This was immediately after moving off having been parked overnight.

 

Temperatures were minus 8 and minus 6 respectively. It resolved within a hundred yards or so of moving off. Has been fine both days since.

 

It was as if there was insufficient (no) assistance to the brakes. Has anyone come across this before (are the low temperatures a red herring)?

 

2016 150hp 2.0 TDI L&K 16,500 miles.

 

Thanks in advance.

 

Bill

Pump the brakes then put the foot-brake on before starting and see if the peddle drops when starting the engine.

1 minute ago, Urrell said:

Pump the brakes then put the foot-brake on before starting and see if the peddle drops when starting the engine.

 

Thanks for your input Urrell. I have many years experience in the Motor Industry but have not plied my trade as it were for some 15 years or so. It reminded me of the brake pump failure on Fiesta diesels over twenty years ago. How Ford managed to convince the DVLA not to issue recalls for that amazed me. it was a truly frightening experience if it failed whilst driving.

 

Yes I understand that will show if assistance is there. My thought was if anyone has also experienced this concern. Didn't think too much about it first time. Didn't enter my head the next morning until it exhibited the same symptom.

 

Has been fine since. We have had some really low temperatures up this neck of the woods over the years and neither of my diesel Yeti's have done this. It just may be coincidence the temperature thing but I was interested if any other member experienced the same and under what circumstances.

 

Many thanks for your support.

 

Bill

I had a problem when the pedal on my new Yeti went down to the floor on a swooping bend in Wales,

a quick pump and it was back to normal, the dealer found "a little air in the system" something to do with

a "porous seal"

Best get the Brake Fluid H2o content checked even though a pretty new vehicle and the First Brake Fluid Change is due at 3 years and then every 2 years.

It was first at 2 years just a few years back.

 

There is 'Brake Assist' settings available in the 'Disability Settings' and the adjustment can be made from the Factory Setting, 

this should not be required though if the brake assist was good when the ambient temps are above freezing.

Might it be possible that the brake pads were wet when last used and then frozen in place in the caliper until a little warmth released them?

8 hours ago, weasley said:

Might it be possible that the brake pads were wet when last used and then frozen in place in the caliper until a little warmth released them?

 

I think you probably have cracked it Weasley. I have been turning it over in my head since it happened - and making a mental comparison with the Fiesta brake pump failure. The Fiesta failure was a pedal as hard as a rock - this (in hindsight) wasn't as bad as that. I had thought about the many permutations that could have given rise to this and, though I have never experienced it before, it could be that indeed.

 

Prior to parking I left the main road and entered our cul-de-sac which was heavy with wet snow. This may just be what happened.

 

Have you heard of this before? I certainly haven't. But an interesting theory.

 

Cheers, Bill 

Pads sticking to rear discs is not unknown, especially at the moment with all the snow and salt on the roads

9 hours ago, AwaoffSki said:

Best get the Brake Fluid H2o content checked even though a pretty new vehicle and the First Brake Fluid Change is due at 3 years and then every 2 years.

It was first at 2 years just a few years back.

 

There is 'Brake Assist' settings available in the 'Disability Settings' and the adjustment can be made from the Factory Setting, 

this should not be required though if the brake assist was good when the ambient temps are above freezing.

 

Thanks Awaoffski

 

Discounted the water content in the brake fluid. Although hygroscopic, the combined fluid (water & brake fluid) is nevertheless still a liquid and as such incompressible.

 

The issue (as I am sure you are aware) with h2o in the brake fluid is that in extreme temperatures at the callipers the h2o would boil off and induce brake fade (pedal falling away under pressure).

 

Conditions too cold to induce that effect.

 

Many thanks for your response though. Not been a fan of the brakes of either of my Yeti's (and my high speed days are long gone) and am considering the bigger disc option to improve response.

 

With optimised brakes, bigger external mirrors (although I am now well used to them) and less fiddly heater controls it would (to me) be just about perfect. Ah well, that ship has sailed and the design is now frozen in time.  

 

Cheers, Bill

7 minutes ago, Llanigraham said:

Pads sticking to rear discs is not unknown, especially at the moment with all the snow and salt on the roads

 

That I am really familiar with. Vauxhall had (and still have) horrendous issues with that stretching back over 30 years.

 

They haven't seemed able to manage the transition to asbestos free pads and the high metallic content they seem to have used would stick/rust/freeze to the pads often quite ferociously.

 

Cheers, Bill

Issue is overheating / boiling,  also freezing but then if not possible fair enough.    Frozen water in not liquid.

But then it is not unknown.  Just ignore that as i will obviously be wrong.

Edited 14 December, 20178 yr by AwaoffSki

4 minutes ago, AwaoffSki said:

Issue is overheating / boiling,  also freezing but then if not possible fair enough.   

But then it is not unknown.  Just ignore that as i will obviously be wrong.

 

Thanks Awaoffski

 

I certainly won't ignore it.

 

As I don't have the answer I am very receptive to all possible causes. Hadn't considered the freezing aspect of the h2o. Valid point and thanks for pointing it out.

 

Cheers, Bill

I would not, just get a test kit. 

It is not unheard of and i did serve my time in garages in the cold north east.

6 minutes ago, AwaoffSki said:

I would not, just get a test kit. 

It is not unheard of and i did serve my time in garages in the cold north east.

 

My apprenticeship in the balmy Central Belt - more years ago than I care to remember. I do remember one particularly cold winter when the fuel pipe for the garage heating froze (some Elf'n'safety bloke from the council insisted it be routed outside the building) of course that was high water content . Blow torches helped thaw it out (eventually).

 

Cheers, Bill

Every winter i remember the Diesel that is not waxing as it is not @ -15*oC or lower but the water in the fuel filters freezes and engines do not start.

& then water traps in the compressors if not drained freezing and even bursting.  Garage Free Air Compressors commonly so.

Edited 14 December, 20178 yr by AwaoffSki

Well, have used the car more frequently recently and the servo is definitely O.K. It is the front brakes that are rubbish after minus temperatures. A good shove on the pedal and the rears kick in and lock the wheels.

 

Not a happy bunny with this poor efficiency - don't recall this on my previous YETI. (2011 TDI 110 4X4)

 

Anyone else experiencing it?

 

Cheers, Bill 

Certainly not something I have found with mine.

I've not noticed any issues with the brakes on mine this last week, when we've been experiencing sub-zero temperatures and snow.  Sounds like a trip to the dealer/independent VAG specialist garage would be in order.

11 hours ago, lawnmowerman said:

A good shove on the pedal and the rears kick in and lock the wheels.

That shows something is wrong, the anti-lock should prevent that.
Could it be a problem with one or more of the anti-lock sensors?

1 hour ago, Urrell said:

That shows something is wrong, the anti-lock should prevent that.
Could it be a problem with one or more of the anti-lock sensors?

 

Don't think it is that Urrell as it is at walking pace and it stops almost in a nano-second when that happens. it is stationary before the sensors pick up a speed differential.

 

Still some thinking to do - hmmm.....

 

Thanks for your input.

 

Cheers, Bill

Edited 2 January, 20188 yr by lawnmowerman

I wonder if this is nothing more simple than a first brake application wiping the rust off the front discs. I have noticed that mine have rusted quite badly in the last couple of weeks due to the amount of salt spread on the roads.

I'm having similar thoughts to Llanigraham.

Thanks LLanigraham and Ken

 

My wife's Citigo brakes are exemplary by comparison. It gets a lot less use and there can be quite a build up of rust. Apart from a graunching noise on application it does not affect the efficiency in any way.

 

I wonder if the calliper slides are sticking/freezing? Never had to work on them - take it they use slides?

 

Bill 

26 minutes ago, lawnmowerman said:

I wonder if the calliper slides are sticking/freezing? Never had to work on them

They do stick and it's a common problem

This is when I changed the discs and pads on my Fabia. they looked OK from the outside.

 

Hmm...

 

Thanks Urrell.

 

Bill