Argh argh argh, not again!

[highlander]

Toward the end of last year I've been having weird scary brake issues. The pedal has been really inconsistent; spongy sometimes, normal sometimes, and really firm sometimes. It varies from press to press. And sometimes I put my foot down and the car is braking, but the pedal will continue to sink as there is less and less resistance to the pressure from my foot. And scariest of all, sometimes I'd put my foot down, the pedal would move maybe an inch or two before going completely solid, and I would feel the vibration of a motor through the pedal, all the while the car isn't slowing down.

Last month I had the car into the garage and treated it to new brake discs and pads, and the guys found the problem to be a cracked caliper carrier on one of the rears. They fixed that and charged me in excess of £200 (inc. parts, labour, and VAT).

However, the day before I was due to drive up to Thurso (220+ miles each way), I was in the car when the engine management light came on, and the car began running really lumpy. As I was driving down my street, I then heard a constant metallic clunking sound. I parked up and checked it out - my front-left brake caliper had fallen off ...

My brother came round to help me, and we found that the garage had re-used the guide bolts that join the two caliper halves together - you're supposed to change those with the pads, as they get worn out and brittle. They also have Threadlock on them to stop them coming out, and once you remove the bolt, the Threadlock is also removed. So the top bolt had fallen out completely, and the bottom bolt was only finger-tight.

So he took me up to Euro Car Parts and I bought a pair of brake pads (which include the guide bolts) and we replaced all the bolts on the front calipers. This really firmed up the brakes again, and the engine management issue and rough running disappeared. So I drove up to Thurso as planned, and a few times on the way over, the engine light came back on and the car ran like crap.

Took the car to a garage in Thurso and they checked the EML on the diag machine, which told them of an intermittent fault with the no.3 injector (or its circuit). He didn't have any injectors in stock, so I had to take it back to Aberdeen with a sometimes-lumpy engine.

Then this weekend I had to nip down to the shops, so I took the car - on the way back home, the brakes were rubbish. Every time I touched the pedal, that "this pedal isn't moving" thing happened, complete with characteristic hum, presumably from the ABS pump. So I took it to a new garage on Wednesday and it's been there ever since. They phoned me today and this is what they had determined:

- The sponginess in the pedal is going to be a problem with the master cylinder
- The scary "you're not stopping" brakes issue is going to be a problem with an ABS sensor
- The EML is going to be a fuel injector

It's going to cost me £488 (inc vat and labour) to get this problem fixed, making it nearly £700 on repairs in the last 2 months alone!

I strongly suspect I will be told that the car has to go, just as soon as the wifely person is back from her holiday, especially since I won't be picking her up. The car will be in the garage til at least monday.

I love the car but I am getting fed up of throwing money at it

[jonsowman]

Sorry to hear this

One thing that strikes me as odd - I can't see how the "you're not stopping" issue can be the result of ABS sensors - surely the physical braking circuit does not rely on information from the ABS system? Does the ABS light illuminate when it should, and does it come on when the fault occurs? I can see the master cylinder being a possibility though.

With regards to the injector issue, is it definitely the injector? Obviously you don't want to change an injector and find out it's the wiring.

Shocking about the calliper falling off, that's really bad. Glad that didn't cause any further damage to you or the car!

[Bailes1992]

All your braking issues can be explained as a failure of the servo! Would explain the fluctuation in the pedal, the hard, soft etc etc.

Also I've never replaced any bolts when I've worked on the brakes of any of my cars.
I usually clean them, cover them in copper grease and torque them up.

The only reason I'd think they'd snap is because they've been done up far too tight! Probably with an impact wrench!
Think about it! Why would the bolts have any more stress on them once the pads have been changed?

[trem1]

Is your car a diesel ??
If so the rock hard "and you know i mean rock hard feels like its seized pedal" is caused by a failing Vacuum pump, i had this on my last 407 and it scares the sh*te out of you when you go to brake and, no matter how hard you press the pedal you aint gonna stop it.

[jonsowman]

Is your car a diesel ??

'Tis a petrol, 2.2 EW12

[lozz]

Iagree with Bailes,
them caliper bolts Shouidnt of worked loose.

Iwouid of gone and seen the person in charge at the Garage that worked on the Brakes,
that couid of been potentialy lethal,

[highlander]

All your braking issues can be explained as a failure of the servo! Would explain the fluctuation in the pedal, the hard, soft etc etc.

Servo fault can be ruled out simply - turn off the ignition, then pump the brake pedal. It will go solid within a few presses. Then keep your foot pressing the pedal and turn the ignition on again - if the pedal sinks down, the servo is working correctly.

Also I've never replaced any bolts when I've worked on the brakes of any of my cars.
I usually clean them, cover them in copper grease and torque them up.

I hope you used threadlock on the bolts

The only reason I'd think they'd snap is because they've been done up far too tight! Probably with an impact wrench!
Think about it! Why would the bolts have any more stress on them once the pads have been changed?

I don't think the missing bolt snapped, I think it fell out because there was no threadlock on the bolt - that had all come off when they removed the bolts. The bottom bolt was still there, but was finger-tight. The bolts on the opposite caliper had worked loose too, but not quite as badly.

[highlander]

Sorry to hear this

Not half as sorry as me - I'm skint!

One thing that strikes me as odd - I can't see how the "you're not stopping" issue can be the result of ABS sensors - surely the physical braking circuit does not rely on information from the ABS system? Does the ABS light illuminate when it should, and does it come on when the fault occurs?

It doesn't light up unless the ABS system is actively preventing the wheel from locking up. The hum I hear when that fault kicks in sounds like the noise the ABS pump makes, and it vibrates through the brake pedal.

Regardless of whether that'll fix the "I'm not stopping" issue or not, that needs fixed anyway - once or twice in the last few months I've had the ABS Defective warning kick in, and then start working again - including on Wednesday morning when I took the car to the garage. INTERESTINGLY, the "I'm not stopping" issue was constantly there, right up until the point when the ABS warning lights flashed up - at that point, the brakes behaved as normal...

is it definitely the injector? Obviously you don't want to change an injector and find out it's the wiring.

He used a multimeter and read the input voltage coming in to all four injectors - same value on all four. He then checked the electrical resistance on all four injectors themselves, and on the number 3 injector, the resistance is considerably higher. Sounds like a knackered wire inside the injector to me, intermittently breaking contact.

[Bailes1992]

You don't need to use thread lock on the bolts. Never have! In fact I don't think manufactures use it what so ever! As long as the bolt is on good condition, well greased and torqued up correctly then there is really no need!

[highlander]

You don't need to use thread lock on the bolts. Never have! In fact I don't think manufactures use it what so ever! As long as the bolt is on good condition, well greased and torqued up correctly then there is really no need!

The old bolts looked rusty as f*ck (they were very, very obviously the old bolts that were on the car from the last time it had new pads), and there was a distinct band of colour where there had previously been threadlock.

When we went to EuroCarParts, they didn't sell replacement bolts, but they were included with packs of brake pads, so I spent £20 on a pair of Pagid front pads. The shiny new bolts included with those pads were also treated with threadlock.

[Bailes1992]

Very strange. Removed my caliper carrier bolts today, they had not been removed since the car was built 4 years ago and there was no traces of threadlock.
The rear brakes have never been touched in 4 years / 100k and none of the bolts on the rear brakes had threadlock on them either?

[lozz]

The Main carrier bolts, the ones that go in to the hub/Bearing carri'er normaly have threadloc on,

carrier bolts.jpg

My guess is -The carrier bolts have nyloc on to prevent,vibrational loosening,
the slider bolts dont /wouidnt need it as they got the rubber dampners.

[jasper5]

The slider bolts don't always have threadlock on them, usually if they are tightened properly they don't come loose.

You should have gone back to the original garage and complained bitterly and made them sort any brake issues out without charge! I'm sure they would have been so horrified that they would have been falling over themselves to sort it out.

Regarding the intermittent injector fault, my solution with Peugeot and Citroen injectors is to swap the injectors round....1 for 4 and 2 for 3 etc, this usually sorts out injector problems, personally I've never had to replace an injector in this situation.

When my front and rear ABS sensors failed recently on my 407 I didn't have any braking faults, only the ABS/ESP light on.

[Welly]

Sorry you're having this trouble Highlander, couldn't have come at a worse time either. I've just had a £320.00 bill on mine in December then this month is the MOT (£50.00), the reversing light switch (£30.00 + 1hr labour) and then the road tax (£148.00 for 6 months, and that's all it's getting) the whole lot is going on the credit card

I think they forgot to tighten those bolts before they put the wheel back on.

The injector/electrical fault is the worst as there'll be a bit of trial and error going on until it's fixed proper. Jasper's suggestion sounds very good.

Let us know how you get on.

[steve_earwig]

The mechanic here never seems to renew those caliper bolts, I'm not sure if it's a good idea but he's been doing it for years so I'd have thought he wouldn't still be doing it if there was any chance the caliper could fall off. I'd have been straight back to whoever it was who worked on them last making endangering my life and suing their arse off noises

As Jasper says. swap the coils around, if the fault moves it's a coil, if it stays still it's something else.

Don't talk to me about spending money on cars I can't help thinking if I hadn't funneled so much into this stupid toy truck thing I'd have enough to buy an all singing and dancing pc, instead of having to borrow one to get online