Technical Changed rear drums and have some issues...

[dumbledore]

Decided to replace my rear drums as the old one where worn out and the handbrake could not be adjusted any more.
I replaced the drums and now handbrake is working perfectly. However when driving I feel there is some pulsation at the pedal that I did not have before. So I am assuming is something to do with the new drums. Also there seems to be too much bias towards the rear. So I decided to back off the handbrake cable adjuster so the handbrake lever can move a couple more clicks. The brake bias seems to be much better after this change, but still I can feel a bit of pulsation. Is this a matter that the brake shoes at the rear will need to ware in with the new drums for a while? I did not replace the shoes as they were OK and also did not try to reset the automatic adjuster as I could not figure out how to do it without removing the brake shoes.

 

[s and b]

you dont say if replacement drums are new or second hand but either way shoes wear into drums so old shoes on new drums wouldnt be right
nor would old shoes on second hand drums
you really need to back off the handbrake cable and adjust whatever you have up properly because otherwise if shoes tight in drum and rubbing then after a drive theres a possibility drums got that hot the heat has transferred to the brake piston then to brake fluid causing boiling and no footbrake

not sermoning by the way just trying to help

 

[portland_bill]

Pedal pulsing is usually due to discs with a varying thickness, or drums that are oval. Were the drums new? Whatever, get them off and measure the internal diameter, at least four places, better 6-8. You'll need a vernier caliper.

 

[dumbledore]

Yes, the drums are brand new. So hope the shoe can ware in after some drive. I am not going to go hard on them until the pulsing goes away. Backing the cable off seems to have improved things. So I test them again tomorrow.

 

[portland_bill]

If the drums are oval, the problem will not go away. The longer you leave it the worse it will get and the less likely you are to get them exchanged for good ones. Get them measured.

 

[s and b]

If the drums are oval, the problem will not go away. The longer you leave it the worse it will get and the less likely you are to get them exchanged for good ones. Get them measured.

its the old shoes rather than new drums causing the issue
maybe if he deglazes them they might bed in easier
still not ideal though

 

[portland_bill]

I disagree that old shoes will cause pedal pulsing. This is the pedal pushing back at you, then sinking as the fluid moves back and forth in the system. Shoes that are not concentric with the drum will just press on a smaller area. A drum that is oval will allow the shoes to move out, then pushed back in, causing the pedal pulsing. The same effect can be caused by a variation in disc thickness.

If the problem has occurred with the new drums, they would be the most likely cause. Unless he's managed somehow to fit them offset.

 

[s and b]

im clutching here but bear with
new drums will be nearer to shoes than old ones
so
is it not possible the shoes are now contacting sooner at this point so causing pulsing
im thinking middle to lower part of shoe as it pivots

 

[dumbledore]

I am still testing things out. I do not believe the new drums are the problem as they are decent brand made by Pagid.
I do believe is related to the shoes, and/or shoe adjustment. Also to add is that the pulsation does not occur always. It appears to happen more when the drums are cold. If I do a few emergency braking and under heavier load the pulsation actually is less or even gets unnoticeable. Also I did think I backed the handbrake cable but I think that was not the case, so I still need to see if that has an effect. The new drums have shifted the brake biased more to the rear than what I like. This behaviour maybe is what it should be as the old drums where worn out so the rears naturally where not doing much braking.

 

[blu73]

so long as the fronts lock up before the rears the bias is ok