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Hot brake drum NSR

Posted: 08 Apr 2019, 18:40
by DoubleOSeven
I outsourced a NSR wheel bearing replacement, couldn’t face the 46mm nut. They also managed to separate my early tie rod ends to arms and even they struggled they said. Anyway, the handbrake light is always on now and the drums are getting hot after a short run. OSR staying cool.

I’m guessing they may have put the adjuster in back to front so the brake pads are not self adjusting. I’d like to pull the drum myself to see but don’t know which way to turn the star, flick it up or push it down, from access hole?
2nd question. I think the drum will still be a challenge to get off the hub, any tips on this. Eric the car guy said use M8x1.25 bolt in the two holes which always have the fixings missing but a. They are not M8 and b. Well, what size are they, will it work?

Need to learn brakes, so I’m starting here.

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Re: Hot brake drum NSR

Posted: 08 Apr 2019, 20:32
by bigherb
Flick up to release (both sides). Although you have to use some force to overcome the ratchet.

Re: Hot brake drum NSR

Posted: 08 Apr 2019, 21:18
by davidoft1
The bolts are m7, I would guess by 1mm they aren’t a necessity, as the handbrake light is under the handbrake itself check something has rolled under it and keeping it up

Re: Hot brake drum NSR

Posted: 15 Apr 2019, 15:32
by DoubleOSeven
Flicked up to release the pads, but this brake drum is not coming off. Any ideas?
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Re: Hot brake drum NSR

Posted: 15 Apr 2019, 21:06
by 937carrera
Usual problem is that the drum is worn and has a lip on the inner edge (in your case the other cause rust shouldn't be a problem as it's been dismantled recently) .

You'll need to fully wind the adjusters back and may have to use some judicial force to get the drum over the shoes. Turning while pulling can work

Hot brake drum NSR

Posted: 16 Apr 2019, 10:03
by DoubleOSeven
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Massive lip on drum is why I couldn’t get it off. Puller and club hammer used.
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Re: Hot brake drum NSR

Posted: 16 Apr 2019, 10:08
by 937carrera
:)

Now measure the drum diameter and compare it to the wear limit which is on the outside of the drum. I suspect you will need to replace them, better to do that before one of the pistons pops out while in use :wink:

Re: Hot brake drum NSR

Posted: 16 Apr 2019, 10:47
by DoubleOSeven
Cheers - I'll replace the drums and replace the back plates while I'm at it all round.

Conclusion: Brake shoes are within limits (new in fact) and fitted & adjusted correctly. Handbrake works @ 3-4 ratchet. I'm now happy I can drive it without concern.

Handbrake warning light always on, but no physical link to rear drums so that must be faulty switch (113 947 561 H), brake fluid at correct level and bled properly.

Re: Hot brake drum NSR

Posted: 16 Apr 2019, 11:00
by davidoft1
DoubleOSeven wrote:Cheers - I'll replace the drums and replace the back plates while I'm at it all round.

Conclusion: Brake shoes are within limits (new in fact) and fitted & adjusted correctly. Handbrake works @ 3-4 ratchet. I'm now happy I can drive it without concern.

Handbrake warning light always on, but no physical link to rear drums so that must be faulty switch (113 947 561 H), brake fluid at correct level and bled properly.

If there’s nothing wrong with the original drums and they are working and within spec grind the lip off and use them, aftermarket drums can be hit and miss, what’s wrong with your backing plates ?

Re: Hot brake drum NSR

Posted: 16 Apr 2019, 13:00
by 937carrera
New shoes and worn drums are the worst combination for getting drums off.

You can grind the lips off as suggested, I have done that, but I have also had to simply replace them due to wear.

As said, why do you need to replace the backing plates- fair bit of work for no benefit unless they are really trashed

Re: Hot brake drum NSR

Posted: 16 Apr 2019, 14:30
by DoubleOSeven
Need to measure width of drums but have filed off the lips for now with Dremel. Thanks for advice on repo's not being as good as factory. Backing plates have holes up front and back, so ingress of water will be an issue. Got some Holts exhaust paste in their for now, blocking the holes.

I've changed the handbrake switch (same as interior light 'door' switches as it turn out), but no change. So, it is always on and glows a bit brighter when pressed?

Re: Hot brake drum NSR

Posted: 16 Apr 2019, 14:38
by 937carrera
DoubleOSeven wrote:Got some Holts exhaust paste in their for now, blocking the holes.

Chemical metal is a better solution - the quick set type goes off in 5 minutes.I used it to repair backing plates on another car last year (replacements not available), which allowed handbrake return springs to be fitted, avoiding an MOT advisory.

On the handbrake light it's an uncomplicated switch, sounds like there is an extra feed route or the wiring is wrongly providing an earth route for another circuit through the bulb

Re: Hot brake drum NSR

Posted: 16 Apr 2019, 17:36
by DoubleOSeven
Yeah. I’ll check the connector on the brake fluid reservoir.
F9 Handbrake
F34 Brake Fluid Level
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Hot brake drum NSR

Posted: 16 May 2019, 18:22
by DoubleOSeven
Switch was ok. Topped up brake fluid, no sign of any F34 switch on my ‘84 for brake fluid level though. Pulled connector from the rear of the handbrake lamp switch and pulled switch itself from binnacle. Cleaned terminals on switch, fixed! Handbrake light now goes off.
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I’m not convinced I had the switch 180 degrees out, may have been!

Hot brake drum NSR

Posted: 03 Jun 2019, 13:30
by DoubleOSeven
Brake fluid on floor beneath pedals and empty brake fluid reservoir = ? (answers on a postcard please?)

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^^ My guess