Rear brakes temperatures

[Clarkj93]

So had a siezed rear caliper, brakes were almost steaming after a gentle drive across the motorway for 20 minutes. Decided to buy a refurbished set on ebay with a warranty included. Both calipers now fitted and brakes bled (still a bit spongy but think I need to do  a proper pressure bleeder job rather than just the gravity technique), I noticed after another gentle drive since along the motorway that the rear brakes were not hot but noticeably warmer than the front brakes (just to add I have some minor brake ducting in the front and dust shields all removed).

So I'm wondering if any other mk5 owners can clarify if this is normal behaviour? Is the fact the rear has a smaller caliper, smaller solid disk, less cooling contribute to this? Or do we reckon there is still something up? I'm in the process of re-greasing everything again now just in case and also the handbrake cable is not over tightened, if anything it is loose as it can be pulled off the lever with a little bit of force but is tight enough it wouldn't come loose on its own accord.

Just to add its not the temps I'm concerned about its the rear brakes possibly applying pressure when they shouldn't be. But possibly with less cooling factors compared to the front maybe it's normal behaviour? Can't say I've ever noticed on any car before if fronts or rears are warmer than the other!

[Jb55]

Can’t help but any chance you can pm a link or stick a link in here to the rear calipers you brought as I’m after a set , cheers 

[Clarkj93]

Can’t help but any chance you can pm a link or stick a link in here to the rear calipers you brought as I’m after a set , cheers 

https://www.ebay.co.uk/itm/Volkswagen-Golf-MK5-GTI-2003-2009-MK6-GTI-Rear-Brake-Calipers-POWDER-COATED-/164425013666?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=710-127635-2958-0

I kind of wish I bought new now as I hear even refurbed ones don't last nearly as long as new ones but for 125 quid it is a bargain. Another member told me to ask for the 41mm caliper (38mm is the standard one) which I did, they just needed an extra couple days to turn it around if that floats your boat.

[Hypertuned]

Logically I can't see the rear brakes getting hotter than the fronts, under normal conditions. On a hot hatch the front brakes do 70% of the braking (if the vehicle is travelling forwards).

Sent from my SM-N9750 using Tapatalk

[pudding]

In terms of general behaviour, the rear brakes do seem pretty active compared to other FWD cars I've owned.  My rear wheels tend to get almost as brake dusty as the fronts over a 1000 miles or so.

But in your case, something is definitely not right if a gentle cruise along the motorway is making the rear brakes hot. Did you file back any corrosion on the carriers to make sure the pads can slide smoothly, and also clean/grease the sliding pins?

Having had rear calipers let go on me also, the rear wheels definitely get roastingly hot when jammed on, but fully working ones don't heat up the rear wheels at all, unless I've just done a lot of heavy braking.

I do an 80 mile commute every day and I occasionally check the temp of the rear wheels, and they're always cold.

[FatWelshBoy]

Is it both sides? I have one rear wheel that gets slightly warm and I think it might be the wheel bearing, doesn't sound noisy and the wheel spins free enough but I'm 100% sure it isn't heat from the brakes. I can't recommend people try touching the disc with a finger but I purposely went for a gentle cruise using minimal brakes and coasted the car to a stop on a slight hill. The disc was cool to the touch but the alloy wheel had very slight heat build up, the other alloys were cold. Other than a bearing I'm not sure what else it could be.

[pudding]

Take the wheel off and look for bluing/discolouration of the bearing hub, and/or signs of grease seeping past the seal.

[Clarkj93]

Thanks chaps. Yeah the shims were clogged with lots of sticky grime, wound pistons back, replaced the guide pins with fresh grease and cleaned the crap off the shims and pads and greased it all up again and temps seem normal compared to the front now. Just careless installation from my part I think! Will keep an eye on it though just in case.

[Clarkj93]

R tech today reckon they are still binding but just slightly. Annoying! I noticed the passenger side caliper handbrake lever is a couple of mm off the stop, where as the drivers side handbrake levers is resting on the stop. The cable seems slack though. Not sure if this could be the issue? The caliper pistons also winds back with ease so they don't feel "sticky" or anything. Running out of ideas

[pudding]

If the handbrake mech isn't fully retracting, that could indeed be your culprit.  Unhook the handbrake cable from that caliper and spin the wheel by hand to confirm mate.

[LC5F]

Are you sure the HB cable isn't sticking?
Did you clean and grease where the pads slide on the carrier?

[Clarkj93]

Car is going on stands for a little while after the weekend so will try and find out how it's behaving. Doesn't look it the cables sticking when I've checked but yeah will have to double check everything. I took the pads sliders off and wiped them down and greased them and also the pads up, didn't use a file just a rag so maybe that was a mistake but looked like it was greased enough to not be an issue.

[pudding]

Did you replace the stainless shims? Normally get a fresh set with new pads. Old shims re-used multiple times tends wear in a step, which can cause pad bind.  The rear brakes don't use a lot of force compared to the fronts, so doesn't take a lot to make them stick.

How many clicks on the handbrake locks the car steady?  I adjust it to 3 clicks to lock (think the MOT is 4, maybe 5) which gives the cable a bit of slack in case the calipers are slow to spring back.  My missus MK6 locks on 1 click and they occasionally bind as a result.  Another job for the list 

[Clarkj93]

Pretty sure the shims came with the last set about a year ago only. The handbrake if anything is a border line mot pass as it is definitely much longer than before but does stop the car.

Currently changing suspension so while I was doing the rear had another look at the rear brakes.

I decided to file down the shims this time. Left is before and right one is after.



After greasing everything very well I tried to replicate with my hands the pads sliding down the shims and felt not so easy tbh so decided to file down the pegs on the pads about 0.2mm in width, they feel much easier to slide up and down the shims now but without any new unusual kind of movement.



Everything greased very well then as you can see



See how we get on with this when the cars supporting its own weight again. Need to also take another look at that handbrake lever on the other side as it is slightly different to this side I've done.

Not sure if this is a terrible idea with sanding down the pegs but seemed OK to me and frankly I will probably be changing them in a few months anyway if I've messed them up.

[Clarkj93]

Pretty sure the shims came with the last set about a year ago only. The handbrake if anything is a border line mot pass as it is definitely much longer than before but does stop the car.

Currently changing suspension so while I was doing the rear had another look at the rear brakes.

I decided to file down the shims this time. Left is before and right one is after.



After greasing everything very well I tried to replicate with my hands the pads sliding down the shims and felt not so easy tbh so decided to file down the pegs on the pads about 0.2mm in width, they feel much easier to slide up and down the shims now but without any new unusual kind of movement.



Everything greased very well then as you can see



See how we get on with this when the cars supporting its own weight again. Need to also take another look at that handbrake lever on the other side as it is slightly different to this side I've done.

Not sure if this is a terrible idea with sanding down the pegs but seemed OK to me and frankly I will probably be changing them in a few months anyway if I've messed them up.

So just incase anyone comes across this in future and sees my modification and thinks " yeah that sounds a good idea".... don't do it terrible idea! Pad contact now is very strange it's touching the disk in a very uneven way as if it's got tons of grooves on the pad material and is obviously not sliding across and pressing firmly against the disk and at slow speed I can hear it dragging on the disk on every rotation.