Strange wobble on front end?!?!

[dexyowl]

Hi. 4 months ago, I had a sudden case of 'extra brake pedal travel'.

Soon afterwards, I developed brake pedal wobble and steering wheel wobble (Octavia Diesel Estate 2003)

Warped discs were suggested, so I had new discs and pads fitted.

The wheels were balanced and tracked on the very same day.

It ran like a Rolls Royce for 1,800 miles, then the problem came back.

Excess brake pedal travel, followed by pedal and steering wheel wobble. Very strange?!

All linkages, brackets, bolts, and other gubbins were thoroughly checked.

The parts Company very kindly replaced the discs (they're a great bunch)

1,500 miles later, the problem returned. The parts company told me that the earlier returned discs were perfect and were NOT the reason for the pedal travel and wobble. 4 Garages told me that it HAD to be the discs, as the problem went away when they were replaced. Any other cause would be present with old discs or new. It looks and sounds the logical conclusion, but patently, reality suggests otherwise. 

Even so, my garage suggested a bad batch of 'weak discs', so I bought (and had fitted) very good quality discs and pads.

800 miles later (a couple of days ago)  the brake pedal travel has increased (very quickly), and I'm fully expecting the wobble to return in the following week or so.

IF it's a bearing, wouldn't the car be affected ALL the time? Similarly, IF it's a hub, wouldn't that be present all the time?

IF it's the Caliper, wouldn't the symptoms be present all the time?

Perfection to wobble in around 1,000 miles. Has anyone any idea what's going on?

Any help would be appreciated.

Thanks in advance.

[kellarj93]

I think I am having the same issue. I 've just had my shock absorbers, springs, bushings and control arms changed. The brake pedal travel is way too much and there is metal grinding noise probably from the calipers touching the wheel. It may be worn discs but this isn't confirmed yet as I am going to have an wheel alignment in August so I will see how it goes. Also, the front end is sitting lower than the rear, I have no clue about that.

Edited 27 July, 2019 by kellarj93

[mac11irl]

Wobble or juddering caused by discs highly likely, but after 3 changes if disc.... The pedal travel issue sounds like a caliper problem.. id suggest a leak/air getting in somewhere. The reason its perfect after the change - any half reputable garage is going to have bled the system after work on the brakes. Over the next 1000miles, the leak is building enough to be noticable 

[dexyowl]

On 27/07/2019 at 23:45, mac11irl said:

Wobble or juddering caused by discs highly likely, but after 3 changes if disc.... The pedal travel issue sounds like a caliper problem.. id suggest a leak/air getting in somewhere. The reason its perfect after the change - any half reputable garage is going to have bled the system after work on the brakes. Over the next 1000miles, the leak is building enough to be noticable 

Thanks. The brakes weren't bled, (I watched them do the work). I noticed yesterday though, that the first time I used the brakes, about 200 yards from home, the pedal went almost to the floor. I thought that they weren't going to work at all, but a couple of pumps later, they were back to what they were. That is, still too much pedal travel, but as yet, no wobble.

I expect the wobble to kick in in around 500 miles or so, or maybe it could be a tad later, as these discs are a step up from my usual ones.

[mac11irl]

Get the brakes bled properly at a different garage... 

Pedal shouldnt go to the floor after they give you back the car...  they should have that taken care of before you leave...

[dexyowl]

On 27/07/2019 at 23:44, kellarj93 said:

I think I am having the same issue. I 've just had my shock absorbers, springs, bushings and control arms changed. The brake pedal travel is way too much and there is metal grinding noise probably from the calipers touching the wheel. It may be worn discs but this isn't confirmed yet as I am going to have an wheel alignment in August so I will see how it goes. Also, the front end is sitting lower than the rear, I have no clue about that.

I don't have any sounds to give me a clue. Everything in and around the wheels and suspension has been thoroughly checked, and found to be good. I do maintain the undercarriage very well. It's what keeps me stable on the road when all is said and done. It's been suggested that my ''hub may be going oval'. I don't know how they can check this, and fitting new discs and pads can't suddenly make the hubs 'not oval' can they? Some suggest that it could be a Caliper, but what can go wrong with a Caliper that is intermittent? They're not sticking in any way, so cannot be causing the problem.

There again, if it was a Caliper problem, this wouldn't go away when new discs and pads were fitted ...... would they? If, as suggested, it's an air leak problem, then my Garage will have to investigate why it develops an air leak after 1000 miles, but not after 20 miles. I'll ask them.

Someone suggested that it could be a Bearing problem. They suggested that ''as it got hot, it expanded and caused the problem'' Surely my bearing gets hot every day after a few miles, so why don't I get the wobble the day after my new discs and pads are fitted?

None of it makes sense?

Edited 1 August, 2019 by dexyowl

[dexyowl]

On 30/07/2019 at 16:48, mac11irl said:

Get the brakes bled properly at a different garage... 

Pedal shouldnt go to the floor after they give you back the car...  they should have that taken care of before you leave...

The brakes were fine for two weeks following the disc and pad work, so if excess air was present, wouldn't this show on day one? Everything was fine for two weeks or so, then the sudden pedal travel. You obviously know more than me about cars, but I don't think it's an 'air in the system' problem.

I appreciate your input however. May be you have some other idea?

[SeanRyan]

On 27/07/2019 at 10:38, dexyowl said:

IF it's the Caliper, wouldn't the symptoms be present all the time?

 

What if pistons on one of the calipers isn't pushing properly?

 

So the pads you had wore down, somehow a piston or 2 started pushing incorrectly, either at an angle or something.

You replaced the pads, in doing so the garage pushed the pads into the caliper, forcing the pistons back level again, over the course of 1500 miles or so, they gradually go back to the bad angle or whatever it is and started to push incorrectly again. 

 

That would potentially explain the brake travel and wobble, and the time between service and when it happens.

 

I Could also be completely wrong.

[kellarj93]

On 01/08/2019 at 12:27, dexyowl said:

I don't have any sounds to give me a clue. Everything in and around the wheels and suspension has been thoroughly checked, and found to be good. I do maintain the undercarriage very well. It's what keeps me stable on the road when all is said and done. It's been suggested that my ''hub may be going oval'. I don't know how they can check this, and fitting new discs and pads can't suddenly make the hubs 'not oval' can they? Some suggest that it could be a Caliper, but what can go wrong with a Caliper that is intermittent? They're not sticking in any way, so cannot be causing the problem.

There again, if it was a Caliper problem, this wouldn't go away when new discs and pads were fitted ...... would they? If, as suggested, it's an air leak problem, then my Garage will have to investigate why it develops an air leak after 1000 miles, but not after 20 miles. I'll ask them.

Someone suggested that it could be a Bearing problem. They suggested that ''as it got hot, it expanded and caused the problem'' Surely my bearing gets hot every day after a few miles, so why don't I get the wobble the day after my new discs and pads are fitted?

None of it makes sense?

Got my brakes bled again today, there was quit a bit of air in the rear system, but It is much better now. I have to change the front brake discs and pads as the rotors are warped (because of misalignment) and pads have uneven wear. Other than that, everything is fine. I am going to workshop on thursday for the wheel alignment and then have the car tested (like what MOT is in UK).

[mac11irl]

Well done. Hopefully all will be good after the disc change

[dexyowl]

On 05/08/2019 at 00:15, kellarj93 said:

Got my brakes bled again today, there was quit a bit of air in the rear system, but It is much better now. I have to change the front brake discs and pads as the rotors are warped (because of misalignment) and pads have uneven wear. Other than that, everything is fine. I am going to workshop on thursday for the wheel alignment and then have the car tested (like what MOT is in UK).

I'm having my brakes bled (and the brake fluid changed) on my next service.

My pedal is still 'travelling', but, as yet, no sign of wobble or vibration.

We'll see what happens in 500 miles time.

[dexyowl]

On 01/08/2019 at 15:28, SeanRyan said:

 

What if pistons on one of the calipers isn't pushing properly?

 

So the pads you had wore down, somehow a piston or 2 started pushing incorrectly, either at an angle or something.

You replaced the pads, in doing so the garage pushed the pads into the caliper, forcing the pistons back level again, over the course of 1500 miles or so, they gradually go back to the bad angle or whatever it is and started to push incorrectly again. 

 

That would potentially explain the brake travel and wobble, and the time between service and when it happens.

 

I Could also be completely wrong.

Sounds very feasible. I'll suggest this to my garage and see what they have to say.

Thanks!

[dexyowl]

Further update 9th September 2019. The pedal and steering wheel wobble hasn't come back as yet (it must be 2,000 miles since the disc and pad change) so maybe it was a poor batch of discs. I'm still expecting some sort of malfunction though.

I reckon that during the latest replacement, the Garage may have improved something in the disc / pad area without realising it? I'm still not confident.