Parking Brake problems after disc change

[Wighty]

Yesterday I put new read discs and pads in the CLK (all Brembo parts) . When I got it all together at the end and test drove it the parking foot pedal was on the floor before the parking brake held the car on a slight slope .
Today I went out to try and adjust the knurled adjuster nut inside the rear disc , initially I tried to adjust it be removing one wheel nut and a slim screwdriver . I couldn't get the nut to turn .
I took the rear discs off again and after some faffing around took the knurled adjuster nut out disassembled it and greased it . This got the adjustment working again .
I turned the nut until the rear disc was locked , and then backed off slightly until the disc turned with a very slight rubbing . Did this in both sides .
After a quick footbrake test on my sloping drive , the same thing happened again , foot brake pedal on the floor before the car is just held in place .
All I can think of now is that I may need to adjust the under rear seat cable adjustment nut ? (Job for tomorrow when it has stopped raining )
Before I replaced the rear discs the footbrake was working ok with a few more clicks than the recommended 5 clicks , but it was holding before hitting the floor .
Maybe the new disc is a tiny amount larger inside and this could cause the main cable to need adjustment ?
Any thoughts ?

 

[bembo449]

I don't know anything about the footbrake set up pal but im sure you wil get it sorted

 

[Wighty]

I don't know anything about the footbrake set up pal but im sure you wil get it sorted

I can't see this being the end of my "mechanicking" career

 

[LostKiwi]

Given you've had the parking brake shoes out (or at least disturbed them) after you adjust them operate the parking brake several times to recenter them then readjust. Repeat a couple of times.
Even if the new drums are slightly bigger than old if the shoe adjustment is correct the pedal should be the same.
The adjusters on the cable are only there to allow for stretch in the cables themselves and wear in the rest of the mechanism.

 

[star]

Did you fit new shoes? Old ones will need to wear flat to match new discs or if both are new, they need to bed in.

 

[Wighty]

Did you fit new shoes? Old ones will need to wear flat to match new discs or if both are new, they need to bed in.

Old ones are still in , they had so much life left in them .

 

[Wighty]

Given you've had the parking brake shoes out (or at least disturbed them) after you adjust them operate the parking brake several times to recenter them then readjust. Repeat a couple of times.
Even if the new drums are slightly bigger than old if the shoe adjustment is correct the pedal should be the same.
The adjusters on the cable are only there to allow for stretch in the cables themselves and wear in the rest of the mechanism.

I will give that a the on/off a go a few times .

 

[steveq]

I wonder did you back off the knurled nut too much?
The old shoes will probably rub the new disks slightly as they had the shape of the previous disks.

I suggest that you turn the knurled nut until the disks lock and then just back it off one of two 'knurls' so the disk will turn.
Then you can check the operation of the parking brake. You can always back each side off by another 'knurl' if the parking brake has less than the recommended 5 clicks.

 

[mercmancdi]

Yesterday I put new read discs and pads in the CLK (all Brembo parts) . When I got it all together at the end and test drove it the parking foot pedal was on the floor before the parking brake held the car on a slight slope .
Today I went out to try and adjust the knurled adjuster nut inside the rear disc , initially I tried to adjust it be removing one wheel nut and a slim screwdriver . I couldn't get the nut to turn .
I took the rear discs off again and after some faffing around took the knurled adjuster nut out disassembled it and greased it . This got the adjustment working again .
I turned the nut until the rear disc was locked , and then backed off slightly until the disc turned with a very slight rubbing . Did this in both sides .
After a quick footbrake test on my sloping drive , the same thing happened again , foot brake pedal on the floor before the car is just held in place .
All I can think of now is that I may need to adjust the under rear seat cable adjustment nut ? (Job for tomorrow when it has stopped raining )
Before I replaced the rear discs the footbrake was working ok with a few more clicks than the recommended 5 clicks , but it was holding before hitting the floor .
Maybe the new disc is a tiny amount larger inside and this could cause the main cable to need adjustment ?
Any thoughts ?

Any chance a cable hooked off at rear of hub while you were dismantling and removing the shoes.
Otherwise the ratchet where 3 cables meet may be let off and needs ratcheted
up.

 

[Wighty]

Thanks Steve and Mercman , all good pointers . Now I have had a few hours to think about it , the CLK pedal travel was always much more than my E class which I'm more used to .
I'm hoping that a small change in the drum has caused slightly more movement in the pedal travel and that when I adjust the cables tomorrow I will see a positive improvement .
If I don't , I will probably strip it all down and fit new parking brake shoes and springs because at that point I'm all out of ideas .
Anyway 4 weeks till I need it sorted to drive to France

 

[mercmancdi]

Thanks Steve and Mercman , all good pointers . Now I have had a few hours to think about it , the CLK pedal travel was always much more than my E class which I'm more used to .
I'm hoping that a small change in the drum has caused slightly more movement in the pedal travel and that when I adjust the cables tomorrow I will see a positive improvement .
If I don't , I will probably strip it all down and fit new parking brake shoes and springs because at that point I'm all out of ideas .
Anyway 4 weeks till I need it sorted to drive to France

In my older clk (facelift 06) there was loads of adjustment below rear seat
It was dead handy to get at .

 

[DaveE320CDI]

Hi Wighty, Does this help?
https://www.pelicanparts.com/techar...stment/18-BRAKES-Parking_Brake_Adjustment.htm

 

[gliggsy]

Parking brake shoes should never wear down unless driven with handbrake on, I'm sure you'll find the problem and fix it...

 

[ajlsl600]

think that the radius diff between new old internal disc dia means that just now little contact between old shoes and integral drum .so little area to hold . as above normally there would be no wear on handbrake shoes, never the less i have often seen it .how many of us have driven a bit without realizing its partially on . suggest adjusting so it rubs a good bit ,wheel still turns. run it around for a few days maybe just a little hand/pedal brake on as well at times, check it dont get too hot then re adjust according to book. if this fails go for the new linings and set it up again. thats about how i would try to resolve anyway

 

[Oldspanners]

May be worth having a look at the ratchet mechanism as if the detent isn't holding or a tooth is worn it would be going back to maximum travel each time you used it.
Bound to be something you can fix but like all these jobs it's just finding it. Look forward to sunny open roads in France not too good today though.

 

[Wighty]

Thanks all for the help , got an early start this morning on getting the rear seats out (my dreams overnight that it would have sorted itself out didn't work) .
Seats and center squab thingy out , I lifted the central inspection cover to reveal the adjuster nut for the main cables , where they branch to each rear wheel .
There was a lot of slack in the adjuster nut , maybe 1/2 inch of travel to get the adjustment from 12 clicks flat on the floor to 5-6 clicks which holds the car on the drives slope .
I did a test drive in the middle of all of this with lots of driving backwards and forwards from the sloping drive to the flat road (where adjustments took place) .
I'm pretty happy now as is Mrs Wighty . I know a lot more about handbrakes than I did 3 days ago when this saga started . A lot of hours involved but that's the price of DIY with a low knowledge base .
Total cost £70 rear discs and pads , £5 for long thin screwdriver to adjust the knurled nut .

 

[Wighty]

You can see the clean threads on the adjuster nut which shows how much slack there was

 

[Wighty]

 

[ajlsl600]

Thanks all for the help , got an early start this morning on getting the rear seats out (my dreams overnight that it would have sorted itself out didn't work) .
Seats and center squab thingy out , I lifted the central inspection cover to reveal the adjuster nut for the main cables , where they branch to each rear wheel .
There was a lot of slack in the adjuster nut , maybe 1/2 inch of travel to get the adjustment from 12 clicks flat on the floor to 5-6 clicks which holds the car on the drives slope .
I did a test drive in the middle of all of this with lots of driving backwards and forwards from the sloping drive to the flat road (where adjustments took place) .
I'm pretty happy now as is Mrs Wighty . I know a lot more about handbrakes than I did 3 days ago when this saga started . A lot of hours involved but that's the price of DIY with a low knowledge base .
Total cost £70 rear discs and pads , £5 for long thin screwdriver to adjust the knurled nut .

sorted then ,grand . dont know about you? but i now at age where regrettably all the learning done here has been pretty much forgotten by the next time the issue presents itself again ,and i end up going thru the same damn performance again...as you say price of DIY ,specifically the ageing DIY.

 

[Srdl]

Thanks all for the help , got an early start this morning on getting the rear seats out (my dreams overnight that it would have sorted itself out didn't work) .
Seats and center squab thingy out , I lifted the central inspection cover to reveal the adjuster nut for the main cables , where they branch to each rear wheel .
There was a lot of slack in the adjuster nut , maybe 1/2 inch of travel to get the adjustment from 12 clicks flat on the floor to 5-6 clicks which holds the car on the drives slope .
I did a test drive in the middle of all of this with lots of driving backwards and forwards from the sloping drive to the flat road (where adjustments took place) .
I'm pretty happy now as is Mrs Wighty . I know a lot more about handbrakes than I did 3 days ago when this saga started . A lot of hours involved but that's the price of DIY with a low knowledge base .
Total cost £70 rear discs and pads , £5 for long thin screwdriver to adjust the knurled nut .

Well done, once again, for trying something I wouldn't even think about attempting