HELP - No braking power in emergency situations

[Bosscav]

Hello all,

I guess this an introduction post for me seeing as I just bought a used 2010 SHO with only 17k miles on it a week ago. I'm loving the car but I found this brake issue startling.

Under normal braking the pedal is very spongey and pedal travel is pretty long. The first 60% of the pedal travel doesn't do anything but around 85% depressed then those 4 wheel disc brakes get to grabbin'.

What is terrifying is emergency braking. Let's say a deer jumps out in front of me and I go to mash the pedal; it is stiff as a rock. I'm a big guy with strong legs and I need to stomp that f****r with both feet as hard as possible to get it to stop. It feels like the booster isnot working. I get no braking power and the pedal is rock hard. It's like having no brakes at all.

Driving in traffic is scary as anything because if someone were to cut me off and I'm right behind them then chances are I'm going to hit them.

Any ideas? I can be more descriptive if need be. The dealership I bought it from (a Jaguar dealership) said there's nothing they can do and it is "a characteristic of that car"

Any help is greatly appreciated.

 

[SHOdded]

Does sound like the brakes (including ABS) need to be bled (air in the system). Did you check the fluid level in the master cylinder? Is if full and does it look clean?

Haven't heard of brake boosters going bad on these cars, but it's a possibility if everything else checks out. HAVE heard of master cylinders needing replacement on occasion. So definitely have that checked out. Good time to do a brake fluid flush as well.

 

[Bosscav]

Fluid level looked alright last I checked. Fluid color I believe was dark, can't remember but I will check this afternoon when I get home.

Sometimes the pedal will be hard with no braking power when the vehicle was just started (within 2 minutes) and I'm reversing. Not sure if that helps any diagnosis. I damn near backed into another car because brakes didn't have pressure.

 

[sperold]

Go to a Ford dealership, take a SHO for a test drive, and take it to your Jaguar dealer for them to see what is `typical for the car`.

 

[esfoad]

Could be the rear calipers are frozen. My car exhibited the same symptoms and that's what it was. I had 75K miles at the time but I've heard of others having the issue with low mileage and yours must have been parked a lot since the mileage is so low. Might be covered under warranty. Mine was covered under the extended warranty.

 

[Bosscav]

If I went to the dealer what should I say? Any key words or phrases that will make them cover it under warranty? B2B is done but powertrain and emissions is still covered.

 

[esfoad]

There may be a TSB for this. I think there's a Sticky on all the TSB's for our cars.

 

[Crash712us]

While the factory brakes are not the best. But the problems you describe are not normal characteristic of are cars and your system ought to be looked ASAP.

 

[Feffman]

Hello all,

I guess this an introduction post for me seeing as I just bought a used 2010 SHO with only 17k miles on it a week ago. I'm loving the car but I found this brake issue startling.

Under normal braking the pedal is very spongey and pedal travel is pretty long. The first 60% of the pedal travel doesn't do anything but around 85% depressed then those 4 wheel disc brakes get to grabbin'.

What is terrifying is emergency braking. Let's say a deer jumps out in front of me and I go to mash the pedal; it is stiff as a rock. I'm a big guy with strong legs and I need to stomp that f****r with both feet as hard as possible to get it to stop. It feels like the booster isnot working. I get no braking power and the pedal is rock hard. It's like having no brakes at all.

Driving in traffic is scary as anything because if someone were to cut me off and I'm right behind them then chances are I'm going to hit them.

Any ideas? I can be more descriptive if need be. The dealership I bought it from (a Jaguar dealership) said there's nothing they can do and it is "a characteristic of that car"

Any help is greatly appreciated.

Any more insight into the brake issue?

Feff

 

[Bosscav]

Yes, I have (sort of) figured it out. Both rear calipers were frozen and providing no braking power. I scarily drove that car for over a year with only front brakes, unbeknownst to me...

I now have 2 new calipers in the rear and purchased EBC RedStuff pads all the way around as well as StopTech Sport Slotted Rotors all the way around. It is definitely better but the booster is still lacking in power.

I am looking to trade the car in on a 13+ SHO as they added a bigger booster and MC in 2013.

 

[Feffman]

Yes, I have (sort of) figured it out. Both rear calipers were frozen and providing no braking power. I scarily drove that car for over a year with only front brakes, unbeknownst to me...

I now have 2 new calipers in the rear and purchased EBC RedStuff pads all the way around as well as StopTech Sport Slotted Rotors all the way around. It is definitely better but the booster is still lacking in power.

I am looking to trade the car in on a 13+ SHO as they added a bigger booster and MC in 2013.

When the rear calipers were non-functional did you have a "clunk" in the rear end after heavy braking?

Feff

 

[Bosscav]

When the rear calipers were non-functional did you have a "clunk" in the rear end after heavy braking?

Feff

No clunk noise, it was just hard pedal if you panic stop and soft pedal if you slowly stop. Even still when I stomp on it the pedal has to sink VERY SLOWLY about an inch before grabbing really hard. There's no doubt in my mind that the booster isnt strong enough. I'm considering swapping in the 2013+ booster/MC or even trading the car for a newer model.

 

[Feffman]

So both the left rear caliper and master cylinder needed replacing, along with a software update. Not impressive at 52,000 miles. I pray God this isn't a harbinger of issues on the horizon.

Feff

 

[SHOdded]

Not a typical experience for the SHO owner, Feff, not to worry too much. The most common experience is the lack of OEM rotor/pad prowess. If you wanted to take on an upgrade to '13+ MC/booster setup, there are howto's for that as well.

 

[itwonder]

Have you done a basic brake booster test, like the one at this link: http://www.ebay.com/gds/How-to-Diagnose-a-Faulty-Brake-Booster-/10000000178571669/g.html

Your problem sounds more like a bad master cylinder to me. I'd swap it out. Bench bleed before installation on the car.