Renault Master back brakes

iainbo · 19 Jan 2011

Hi All,

I was changing back pads and discs on my Renault Master 2.5, 2005 model. I managed one side fine. The 2nd side the piston came out - I think I was winding the wrong way!!. Is it just a case of trying to screw piston back in? It seems to be a 4 start left hand thread - hence how I managed to wind it out. I have tried but I'm not having much joy - I haven't got the proper wind back tools - only a big screwdriver which manages to turn it but doesn't put much pressure on it though. Do I need to buy tools, only one I've seen so far was in screwfix - £62!!

Any advice much appreciated.

Also why are brakes like this now - used to be I just loosened the bleed nipple and managed to push or wedge piston back on older cars. changed pads, bled it and all was good.

Thanks,
Iain.

Burnerman · 19 Jan 2011

They are left hand thread and sadly you found out the hard way.....you will need the retractor, and I got one from Laser tools stockists for around £30 trade.
If the disc piston was allowed to retract as per the normal system, the handbrake wouldn't be very good, hence the ratchetting mechanism.
John

iainbo · 19 Jan 2011

Hi John,

Thanks for quick response - reckon I'll need to buy tool - I see a laser one on halfords web site for £33 - is this fairly universal for most vehicles.

I see - the screw back is for the handbrake, think I've only ever done front brake pads - think every car I've had in the old days had drums on back!

Thanks again.

Iain

Burnerman · 19 Jan 2011

Unfortunately Iain the vast majority of vehicles have a right hand retraction thread so your new tool won't get much use, I'm afraid!
Just make sure you get the right one.....
I think Laser do a kit which has both L/H and R/H retractors plus the various anvils - but in practice most bits won't be used.
Thankfully I've never had the piston unscrewed before so maybe you could post back and tell us how things went?
Personally I'm not sure if I prefer discs or drums on the back.....wheel cylinders always seem to be leaking, but calipers get covered in road crap too.
Be lucky!
John

iainbo · 19 Jan 2011

I'll have a go tomorrow and let you know - reckon I'll need some luck!

Burnerman · 19 Jan 2011

Aye I hope it goes well.....just a thought, these retractor tools need to turn the piston and push it back in at the same time - and the retractor has to be completely square (perpendicular) to the piston or they tend to bind. With patience they do work ok.
John

iainbo · 20 Jan 2011

Hi John,

I've ordered a laser tool on ebay, seems to be specifically for renault master and citroen. Less than £30. Will keep you posted. A wee bit cold to be working on van today anyway, freezing fog all day in Glasgow.

Iain

jctilingservices · 21 Jan 2011

another optiion is to use a set of mole grips, grip the edge of the piston and as you turn it in, put pressure on with your hands, it definately worked on my mates 2003 renault master crew cab truck

iainbo · 21 Jan 2011

Success!

I hadn't actually ordered tool last night, I'd found site and was about to order just after I posted my last reply last night, but couldn't order because of paypal probs - couldn't remember password.

So I gave it another go today, jammed shifter in caliper to stop it pushing back as i put weight against screwdriver and turned anti-clockwise and it screwed back in - not often I'm lucky.

Thanks for all advice John and jctiling - before I attempt things in future, I'll ask for advice first!

One thing now - I don't understand principle of it - why, if the threads are engaged, does it not just screw back, why does it need turned and pressure applied.
Iain

gman76 · 22 Jan 2011

Very easy mistake to make - similar setup on Pugs rear brakes, you wind one side back & move on to the next forgetting that it's a mirror image & wind the "same" way - oops!

Burnerman · 22 Jan 2011

iainbo said:
Success!

I hadn't actually ordered tool last night, I'd found site and was about to order just after I posted my last reply last night, but couldn't order because of paypal probs - couldn't remember password.

So I gave it another go today, jammed shifter in caliper to stop it pushing back as i put weight against screwdriver and turned anti-clockwise and it screwed back in - not often I'm lucky.

Thanks for all advice John and jctiling - before I attempt things in future, I'll ask for advice first!

One thing now - I don't understand principle of it - why, if the threads are engaged, does it not just screw back, why does it need turned and pressure applied.
Iain

I'll try to explain as well as I can - or as I think....!
The inside of the piston is hollow, with a female screw thread as you realise. Its the male screw that is turned when the handbrake lever is pulled - this extends out of the piston as the pads wear and takes up the adjustment to keep the pads very close to the disc. The piston does not rotate. So, pressure is applied to the piston as it is turned in, and this prevents the screw from just freely rotating - it effectively halts it against its operating mechanism. Thats how I understand it but I've only had early Mazda MX5 ones apart - and those are manually adjusted.
John

iainbo · 24 Jan 2011

Hi John,

Thank you for the explanation of the braking system. It makes things a lot clearer now.

Brakes back together now, bled them at the one where piston came out and all is good.

Next time I'll ask for advice before starting job.

Many thanks,

Iain.

Burnerman · 24 Jan 2011

Nice one Iain, thats quite an achievement and you should be well chuffed with yourself!

John

jctilingservices · 25 Jan 2011

its nice to be nice aint it, well done mate.

John, thats very easy to understand mate, i never knew any of that before so cheers mate

dennis751 · 24 Apr 2015

A Brake piston wind back tool is available with both left and right hand "Winders" plus some 20 plates (For various pistons) in a plastic case on Ebay for only £18.99 inc of VAT & Postage.
The equivalent Draper or Nu-Tool set is about £130
I've only used it 4 times, but still in 100% condition, although I'm not too sure how it would wear used daily (In a Garage) for example.

Renault Master back brakes

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