Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: Lizzie Zoom on 14 September 2018, 20:23:40

Title: O/s brake oscillation/fluctuation
Post by: Lizzie Zoom on 14 September 2018, 20:23:40
Back in January my car passed the MOT, but an advisory stated that there was an oscalliation/fluctuation on both o/s front and o/s rear brakes.

Decided now I better get to investigating the situation.  The brakes though work fine, unless braking from high speed when I can feel some "fluctuation".

Any thoughts or suggestions please? :-* ;)
Title: Re: O/s brake oscillation/fluctuation
Post by: VXL V6 on 14 September 2018, 20:27:09
Discs warped
Wishbone bushes
Wheel balance

Take your pick!  :D
Title: Re: O/s brake oscillation/fluctuation
Post by: Kevin Wood on 14 September 2018, 21:19:44
If it slows up at low enough speed to be visible on a brake tester it's probably run-out on the disks.

Title: Re: O/s brake oscillation/fluctuation
Post by: Lizzie Zoom on 14 September 2018, 22:08:51
Discs warped
Wishbone bushes
Wheel balance

Take your pick!  :D

Thanks :y

I am having the wishbone bushes replaced over the next week :D ;)
Title: Re: O/s brake oscillation/fluctuation
Post by: Lizzie Zoom on 14 September 2018, 22:09:11
If it slows up at low enough speed to be visible on a brake tester it's probably run-out on the disks.

Thanks :y
Title: Re: O/s brake oscillation/fluctuation
Post by: johnnydog on 15 September 2018, 10:12:02
Unusual though that the two affected brakes are both on the offside.
When the car is parked, is it the offside that gets the weather / rain?
Could be that the offside discs have more corrosion (usually unseen on the inner face), which is causing the problem.
Can it be felt through the pedal whilst gentle braking?
Title: Re: O/s brake oscillation/fluctuation
Post by: Lizzie Zoom on 15 September 2018, 10:58:01
Unusual though that the two affected brakes are both on the offside.
When the car is parked, is it the offside that gets the weather / rain?
Could be that the offside discs have more corrosion (usually unseen on the inner face), which is causing the problem.
Can it be felt through the pedal whilst gentle braking?

No, the car is always garaged.  Only when braking down from high speed (80+) can i feel some "pulsating", but usually nothing at all.

I also thought it was strange that only the o/s brakes are affected, but Vx wanted to charge me £200 (with TC!!) just to look at them, so I am now getting a free brake check at my local very reliable specialist tyre, exhaust and brake dealer.  I will see what they say. :y :y
Title: Re: O/s brake oscillation/fluctuation
Post by: TheBoy on 15 September 2018, 11:04:08
My general diags on this is:

Always repeatable, but no vibration when driving at 80-90 = "warped" discs (warped meaning any out of true)
Intermittent on braking and intermittent at 80-90 = suspension/steering wear
Always vibration at 80-90 = balancing
Title: Re: O/s brake oscillation/fluctuation
Post by: Lizzie Zoom on 15 September 2018, 11:17:40
My general diags on this is:

Always repeatable, but no vibration when driving at 80-90 = "warped" discs (warped meaning any out of true)
Intermittent on braking and intermittent at 80-90 = suspension/steering wear
Always vibration at 80-90 = balancing

Thanks TB! :y

I am pleased that no-one is suggesting any problems with servo's, so the rectification should not be too expensive!! :D :D :y
Title: Re: O/s brake oscillation/fluctuation
Post by: Lizzie Zoom on 15 September 2018, 14:44:00
Well, like any good mechanic, I did what I should have done back in January;  took all the road wheels off, inspected and cleaned the brakes.

All pads, and discs are good, running true.  But,............I found that an amount of crud had built up around the edge of the disc on the o/s front brake and it was not freely turning, catching itself, with a scraping noise, on the caliper / pads!  Cleaned off rusted metal and general muck,with a wire brush, a mallet and screwdriver.  All turns beautifully now, and a road test up to 80 mph, then hard braking, revealed no oscillation / fluctuation that I could detect anyway.

I will now replace the wishbone bushes that have deteriorated, and I believe that should completely cure any problems I may have had 8) ;)

Thanks for all the input, once more it was very useful :-* :y
Title: Re: O/s brake oscillation/fluctuation
Post by: dave the builder on 15 September 2018, 17:15:59
Well done  :)
I like to remove the calipers and give everything a good clean ,lube slides etc just before MOT. gives you the opportunity to check all the suspension etc,identify any possible problems ,rust proof, and ensure the brakes are in tip top working order for the brake test .
Don't bury your head in the sand though, get them covers off and treat any rust ,if the sills or anywhere else is holed,at least you have 4 months to work out a solution  :y
a few hours work now could extend the life of your lovely comfy big vauxhall  ;)
Title: Re: O/s brake oscillation/fluctuation
Post by: Lizzie Zoom on 15 September 2018, 17:31:36
Well done  :)
I like to remove the calipers and give everything a good clean ,lube slides etc just before MOT. gives you the opportunity to check all the suspension etc,identify any possible problems ,rust proof, and ensure the brakes are in tip top working order for the brake test .
Don't bury your head in the sand though, get them covers off and treat any rust ,if the sills or anywhere else is holed,at least you have 4 months to work out a solution  :y
a few hours work now could extend the life of your lovely comfy big vauxhall  ;)

Thanks Dave :y :y

Please see my last post in my "Jacking an Omega" thread.  The car is going to get professional treatment on the rear end, and the sills have been inspecting with no problems reported. :-* ;)
Title: Re: O/s brake oscillation/fluctuation
Post by: TheBoy on 15 September 2018, 20:53:46
Well, like any good mechanic, I did what I should have done back in January;  took all the road wheels off, inspected and cleaned the brakes.

All pads, and discs are good, running true.  But,............I found that an amount of crud had built up around the edge of the disc on the o/s front brake and it was not freely turning, catching itself, with a scraping noise, on the caliper / pads!  Cleaned off rusted metal and general muck,with a wire brush, a mallet and screwdriver.  All turns beautifully now, and a road test up to 80 mph, then hard braking, revealed no oscillation / fluctuation that I could detect anyway.

I will now replace the wishbone bushes that have deteriorated, and I believe that should completely cure any problems I may have had 8) ;)

Thanks for all the input, once more it was very useful :-* :y
My bloody discs, well fronts anyway, never last more than 2 years anyway...
Title: Re: O/s brake oscillation/fluctuation
Post by: Bigron on 15 September 2018, 21:39:14
Rumour has it that there could be a reason for that, TB?

Ron.
Title: Re: O/s brake oscillation/fluctuation
Post by: BazaJT on 16 September 2018, 08:40:02
Discs on mine are about due for replacement but I have had it for 7yrs and they weren't new when I bought it.
Title: Re: O/s brake oscillation/fluctuation
Post by: Nick W on 16 September 2018, 08:55:09
Discs on mine are about due for replacement but I have had it for 7yrs and they weren't new when I bought it.


mine was the same; I got over seven years and 50k miles out of the discs and pads paid for by the previous owner. If I was wearing out brakes and tyres at the rates regularly quoted here, I would have to seriously consider swapping my driving licence for a bus pass.
Title: Re: O/s brake oscillation/fluctuation
Post by: TheBoy on 16 September 2018, 08:55:38
Discs on mine are about due for replacement but I have had it for 7yrs and they weren't new when I bought it.
Normally on Omegas, for those not too heavy on brakes, the inside face corrodes badly, so you still don't see much beyond 3-4yrs :(
Title: Re: O/s brake oscillation/fluctuation
Post by: TheBoy on 16 September 2018, 08:56:54
If I was wearing out brakes and tyres at the rates regularly quoted here, I would have to seriously consider swapping my driving licence for a bus pass.
Milton Keynes does not help, nor do autos.


'onest, guv
Title: Re: O/s brake oscillation/fluctuation
Post by: Nick W on 16 September 2018, 09:48:44
If I was wearing out brakes and tyres at the rates regularly quoted here, I would have to seriously consider swapping my driving licence for a bus pass.
Milton Keynes does not help, nor do autos.


'onest, guv


I wasn't limiting that to just cars.
Title: Re: O/s brake oscillation/fluctuation
Post by: Nick W on 16 September 2018, 09:50:32
Discs on mine are about due for replacement but I have had it for 7yrs and they weren't new when I bought it.
Normally on Omegas, for those not too heavy on brakes, the inside face corrodes badly, so you still don't see much beyond 3-4yrs :(


That's not a specific Omega characteristic, but is true of all single piston sliding calipers.
Title: Re: O/s brake oscillation/fluctuation
Post by: TheBoy on 16 September 2018, 16:04:42
If I was wearing out brakes and tyres at the rates regularly quoted here, I would have to seriously consider swapping my driving licence for a bus pass.
Milton Keynes does not help, nor do autos.


'onest, guv


I wasn't limiting that to just cars.
Not sure I follow?  What other brakes am I eating through...
Title: Re: O/s brake oscillation/fluctuation
Post by: TheBoy on 16 September 2018, 16:06:38
Discs on mine are about due for replacement but I have had it for 7yrs and they weren't new when I bought it.
Normally on Omegas, for those not too heavy on brakes, the inside face corrodes badly, so you still don't see much beyond 3-4yrs :(


That's not a specific Omega characteristic, but is true of all single piston sliding calipers.
Indeed, but GM vehicles seem worse to me. For example, my old R25 was ingle piston IIRC, but the last front discs to go on that were done under warranty, so must have been within the first 3yrs, and we had it for 12yrs.
Title: Re: O/s brake oscillation/fluctuation
Post by: Nick W on 16 September 2018, 16:15:34
If I was wearing out brakes and tyres at the rates regularly quoted here, I would have to seriously consider swapping my driving licence for a bus pass.
Milton Keynes does not help, nor do autos.


'onest, guv


I wasn't limiting that to just cars.
Not sure I follow?  What other brakes am I eating through...


I meant me! I'm just not hard on machinery