Are rear calipers all the same? Quick answer needed

[joeseth]

I have calipers off a '89 320 cab. Are all rear calipers the same? Have heard tourings are different. Also are e36 the same as will be easier to source. Cheers

[Grrrmachine]

Tourings are different, but they're interchangeable. Tourings have a bigger piston, but even the mighty Brianmoooore mixed and matched his calipers with no ill results.

[joeseth]

Sweet so one touring caliper and one normal caliper won't send me spinning off the road and hopefully will be fine for mot?

[Grrrmachine]

shouldn't do. They all use the same brake pads so there's no increase in braking surface area.

[daimlerman]

I think that touring rear pistons are 39mm compared to lesser version's 38mm...
Even the 'Bracknell Special' only got 38mm pistons...

[joeseth]

Got a touring one today luckily so should be up and going tomorrow

[HJG-E30]

shouldn't do. They all use the same brake pads so there's no increase in braking surface area.

Braking surface area has no effect on braking performance (apart from heat dissipation). If the piston in the touring caliper is able to provide more pressure, then the braking will be uneven, regardless of surface area

[pac1982]

shouldn't do. They all use the same brake pads so there's no increase in braking surface area.

Braking surface area has no effect on braking performance (apart from heat dissipation). If the piston in the touring caliper is able to provide more pressure, then the braking will be uneven, regardless of surface area

as above but that aside i would still want at least matching pair at each end just because

[daimlerman]

shouldn't do. They all use the same brake pads so there's no increase in braking surface area.

Braking surface area has no effect on braking performance (apart from heat dissipation). If the piston in the touring caliper is able to provide more pressure, then the braking will be uneven, regardless of surface area

That's odd...

It's a well known modification to Mk2 Jaguar saloon to replace the front caliper with one that gives a 95% increase in surface area,this gives far better braking performance!

Regarding E30 rear caliper,the correct touring spec one has a piston only 1mm larger in diameter,I cannot see that this will give any inbalance if only fitted on one side,although I personally always swap calipers in pairs.

[Jim320i]

Personally, even if someone who knew and had fitted them to their own car said it was fine, I still wouldn't listen. Replace with matching calipers. You don't want to be finding out that at 80mph, they do infact have a difference, for the sake of some more money... I would rather just switch them both. That extra cash you saved not getting, you can't take with you when you pile into a tree

[joeseth]

I've got a mot soon so will see if the brake test shows any difference. I bet there was way more difference in the rubbish drum brakes I had this time last week.

[Brianmoooore]

I've never at any time advocated the fitting of different sized rear calipers on an E30, or suggested it's acceptable to do so. What I have said, is that if different ones happen to have been fitted, then you are unlikely to notice while driving.
If you need to change a saloon caliper, and only touring ones are available, then change both.
The difference in piston area is around 10%, which, if you ever study the brake test results after your MOT test, you will see is not a particularly great amount.

[Grrrmachine]

Didn't mean to put words in your mouth Brian. I just remember that the fact that tourings had bigger pistons only came out on the forum a year or two back, and that people had unknowingly been fitting touring calipers to saloons with no ill effects for years prior to that.

As for braking differences between disc and drum - the difference will more likely be felt in having new pads vs old shoes rather than any inherent weakness of the drum design.

[daimlerman]

As for braking differences between disc and drum - the difference will more likely be felt in having new pads vs old shoes rather than any inherent weakness of the drum design.

The advantage of disc over drum at the rear of a car is not in improved braking,it's more about saving expensive spanner monkey time!

You can visually check both pad depth and disc condition without even removing a wheel,try doing that with a drum brake....

[Jozi]

I think it's 32mm vs 35mm for the piston diameter. I got caught out while refurbing my callipers, the kit I got had seals for the 32mm callipers thats how I found out there was a difference.

I wouldn't be so keen on using two different callipers though

[joeseth]

I had them side by side and couldn't see a difference in piston size by eye. And as for discs vs drums, my pads and prob slave cylinders were shot. The main reason for changing is for looks. There's nothing worse than having a nice set of wheels with nice looking brakes on the front, then looking at the back and having an ugly drum sat in the wheel. Plus then everyone knows you have a smaller engined car