Juddering brakes

GB15

My brakes were juddering occasionally last week so I brought the car into the mechanic and told him to check them out. I thought it may have been the pads wearing thin. Got it back and was told the master cylinder needed to be replaced. He fitted a second hand one. Now I’m getting the same juddering. As before it only happens very rarely but obviously it’s enough to cause concern it being the brakes.

I’m no expert it’s only an idea but I’m thinking it may have something to do with the ABS(sensors possibly?). Assuming the pads were ok seeing as he didn’t mention them and seeing as replacing the master cylinder didn’t do anything is there any other possible cause? Unless the second hand part wasn't good enough...

By the way it’s a 98 Omega (pre facelift).

crosstownk

I'd get the brake discs ckecked as they may be warped - this is the most common cause of juddering.

I've no idea why he replaced the master cylinder - I can't see how this would contribute to the juddering.

Avns1s

If it's when applying the brakes, then likely that the disks are warped.

GB15

Thanks for the replies.

The thing is both before I brought it in the first time and after I got it back I tested to see how the car would react under hard braking. Each time it came to a stop quickly in the normal manner without juddering. It's only ever so often (say twice in the last week since I got it back) it gets a slight judder and then goes back to normal.

The other thing is if it does turn out to be warped brakes what should happen regarding the master cylinder he replaced? It cost 75euro 2nd hand + labour. Am I entitled to this money back for work that was unnecessary?

JHMEG

If the shuddering isn't happening each and every time you brake it sounds like it could be your ABS (operating normally). Do you know what your ABS feels like when it kicks in?

Drive on a wet road and push the brake pedal (when safe to do so obviously) hard and keep it down till you stop. When the ABS kicks in you will feel pulsating in the brake pedal.

Are the front tyres in good condition?

layke

Symptoms happened to a friend of mine. Turned out to be the wheel bearings.

crosstownk

Lets try and narrow it down a wee bit.

How does this judder manifest itself - does the whole car vibrate or just the brake pedal?

To check for warped discs, bring the car to a stop from a slow speed (10kmh) by gently pressing the brake pedal. If the discs are warped you will feel the brake pedal rise and fall as the wheels rotate.

GB15

JHMEG wrote:

Do you know what your ABS feels like when it kicks in?

Yes. There was one occasion a while back where the ABS had to kick in. I could feel the ABS action on the brake pads which jerked the whole car but there was no feedback through the brake pedal like I'm getting now.

JHMEG wrote:

Lets try and narrow it down a wee bit.

How does this judder manifest itself - does the whole car vibrate or just the brake pedal?

As I said its just the brake pedal. I can feel the brake pushing in further than it usually does. The first thing I suspected was worn break pads.

The thing I don't understand is why does it only occur very occasionally. If it were the pads surely once they wear past a certain level they would remain like that. Also I don't think any mechanic who gets a general instruction to check brakes would miss worn pads. I'll give him the benefit of the doubt for now on that point but you never know. I'll call the mechanic tomorrow. I just wanted to have more of an idea of the possible causes.

By the way I have access to another car for a few days as luck would have it (in case people think I'm driving around with dodgy brakes).

GB15

layke wrote:

Symptoms happened to a friend of mine. Turned out to be the wheel bearings.

I'll have to say that to him too. If that is the cause is it an expensive job? This would come back again to the question of what happens when work is carried out that was unnecessary? Is there any comeback?

crosstownk

Warped discs would cause the symtoms to prevelent the whole time. If the discs were worn it will feel like the brake pedal is 'pulsing'. This is more noticeable at slower speeds, but causes vibrations at higher speeds.

Have you checked your tyres for bulges/uneven wear? A dodgy tyre can cause unnecessary feedback through brakes, steering and suspension.

If you can prove to the garage that the work was unnecessary then you should be entitled to a refund. The garage may want to refit the original part, but this rarely happens. I can't see it being plain sailing for you as garages are reluctant to do work for free (the maldiagnosed job), and less reluctant to admit that they were wrong. Simply put, you still have the original fault despite their attempt to repair it at your expense - you didn't get what you thought you were paying for. It's gonna be an uphill struggle all the same.