Topic

Changing the 304mm brake discs was easier than I though But changing the brake pads is not going so well. The pads on a 4 pot caliper are held in by pins. One of the pins drifted out with penetrating oil and a few mins of continuous persuasion with a hammer and centre punch. The other isn't budging. What is the trick to work around this please as im completly stuck ?

Every other set of brake pads I've changed in my life has been a doddle compared to this.

Centre punch? A tapered punch with a pointed tip.

This will only serve to try and spread the pin!
You should use a pin punch, a punch with a cylindrical shaft and flat cut tip

I suspect there were a number of folk on with this at about the same time as when I did those on the tf & there was no shortage of advice. There was nearly as much background radiation as there was after the Big Bang; static & that was the state of everyone’s pins.
The general consensus was replace the lot, pins springs everything & like yours the odd pin came out.
Plusgas, patience, perseverance, rotary wire brush & an old G cramp modified from one job it wasn’t intended to do into another. Best of all good fortune.
M

On day 2 I decided to carefully cut the pins in half with a Dremel. The fronts dislodged easily and then over the next couple of hours I worked with a combination of punch, lots more plus gas, a mole wrench to get some turning momentum and a G clamp til they were out. Glad that's done now and just waiting for the new pins to arrive.

I doubt you’ll require me to tell you but when you replace with new or doing a pad change clean the locating hole & copper grease the pins. This trouble will then be a thing of the past.
M

Airportable wrote:

I doubt you’ll require me to tell you but when you replace with new or doing a pad change clean the locating hole & copper grease the pins. This trouble will then be a thing of the past.
M

You can also use these to alleviate the problem; https://www.mikesatur.co.uk/-MGF-and-MGTF-Stainless-Steel-AP-Brake-Pad-Retaining-Pins
I seem to have recommended Mike Satur's products a few time lately but sadly I am not on commission

I can’t remember now what diameter the pins were, it’s a while ago since I worked on them, I recall it was about 6mm & I had some in my stainless stock drawer. Those who pay any attention to my posts (not many I guess) will have gathered I make a lot of stuff if I’m inclined at the time & I made a set of pins
I relieved the portion between the calliper cheeks, taking them down to 5.5mm (assuming they were 6mm). I was playing with a surface grinder attachment I scrounged & it was a good exercise. I ground down the tops & worked a thread on the other end & screwed & glued a bobble on. All at zero cost, mind it probably took two & a half hours.
M

One way of getting a single pin out is by removing the caliper from the car, taking out the four cap screw bolts that hold it together and twist the two halves away from each other. This cracks the bind on the pin and allows you to remove one half of the caliper from it. The pin will simply knock out from the other half of the caliper.
I find splitting the two halves useful as you can remove the steel slider plates and remove the build up of corrosion under them which lifts the plate and allows debris in. New stainless slider wear plates are cheap to buy. Stripping the caliper also allows a chance to clean and paint it so its all nice and good again!

Sundance

The pins are out finally but you mentioned the slider/ thrust plates which I could do with some advice on. If we are talking about the same parts, elongated U shaped bits of metal that act as shims for the top & bottom of the pads to slide over. Mine are partly damaged on one caliper and though I can see the plates should be removable I had no joy trying to remove them in situ, the allen key bolts are just too tight.

The drivers side was fine but on the passenger side I couldnt work out why the back of the pads wouldnt sit comfortably against the back of the caliper once the pistons were fully recessed. I then noticed the metal slide plates were higher towards the outside than the inside, forcing the pads in towards the disc. This probably explains why the pad wear was so uneven. I carefully sprayed plus gas then brake cleaner under the plates as far as I could to wash out the build up of dirt to make them sit flatter and also ground a marginal amount off the edge of the pads. All ok there but then I noticed 2 suspicious bits of metal on the ground and realised whilst I had been concentrating on the front sections of the U on these plates, the back parts must have snapped at some point and had come away when the original, worn, pads were lifted out.

Now Ive worked on calipers on a lot of cars over the years but these slide plates are new to me and just seem a confounded nuisance. Will it make any difference if I now fit the new pads and pins ignoring the rear section of these slide plates ?. It wouldnt seem to make any difference to braking and the pads fit snugly but are sufficiently free to move as they should, just as they would be in any other caliper. Is this ok or am i looking at a full caliper rebuild for this, which Im guessing would mean the expense of getting both sides done to ensure fully even braking is maintained ?

If you’re rolling up your sleeves & getting to grips with brakes do it by the book & if you’ve not got the book make that your first purchase. Leave nothing out & don’t include anything that’s not shown in the book. If you haven’t got the book & don’t want to buy it, entrust the job to someone who has the book & understands what it says. You’ll most probably have to pay someone to do them but when that child wobbles off the pavement on their bike & you hit the brakes to avoid them you’ll stop.
My observations of your work via your posts tells me that you understand the full ramifications of doing the job right which is the corollary of getting it wrong & finding they’re not working properly when you need them the most.
M

The pins that hold the wear plates in can be a pain, a small impact gun with a hex bit in usually shifts them, I have also had success with a large pair of wire cutters with one cutting face on the outer edge and one in the hex hole. Another way to shift them is a good old hammer and small chisel to tap the outer of the bolt flange around and break the hold of the corroded pin.

I used to replace these bolts with stainless equivalents, but they are a little soft when trying to undo again nest time the caliper is stripped down, so now I fit Titanium ones. Very strong and will not corrode. New wear plates can be bought online if they cannot be straightened good enough.
Note, also re-tap the holes in the calipers, it helps. I also fit new bolts that bolt the two halves together. Top of me head I think they are M10 X 65 mm.

Sundance

Ive decided to take the caliper off this evening, split it on the bench and have a go at getting these little bolts out. If not, a well known F & TF supplier has said to post them to him in Glossop and he will do them for me.

From Mike Satur's site Ive ordered stainless steel wear plates, a set of stainless pins and springs and replacement outer piston seals.

Is there a technique to plug the end of the flexible hose to stop too much brake fluid draining away after ive i removed the caliper ? Ive only ever swapped calipers over immediately before so not had to leave one off for hours or days, not had to worry about this before .