[buzby]

In the ‘old days’, automatic gearbox cars would have larger brakes than manual cars, even for the same engine size in order to compensate for a lack of ‘engine braking’ when driving. Might this be the reason for the varying disc sizes? Certainly on my auto T3, the brakes look bigger than my previous manual D2.

Quite possibly, though as they usually tell you not to use engine braking even on manuals these days it would make sense to just fit the larger brakes on all the models (though we are talking about a company that deleted 2 plastic caps to save money..). I'm in a car sharing scheme at work and our site is up in the Pennines - in the summer the 278mm discs sometimes get a bit fadey going downhill when there's 3 passengers in the car., hence why I wanted to upgrade.

 

[anixie]

No engine braking ? Oh well, there are a couple of 15 mile long downhill stretches which I sometimes travel over and I almost never touch the brakes there (manual car, D4) Just put it in fourth gear and foot of the gas... Would that cause insufficient lubrication of the engine maybe ?

 

[buzby]

No engine braking ? Oh well, there are a couple of 15 mile long downhill stretches which I sometimes travel over and I almost never touch the brakes there (manual car, D4) Just put it in fourth gear and foot of the gas... Would that cause insufficient lubrication of the engine maybe ?

You don't have to worry about lubrication - as long as the engine is turning the oil pump will be turning too. It's more since the move to turbo engines that the engine braking thing has come in - closing the throttle when the engine is still revving should cause the manfold bypass valve to open, which will dump the pressurised air back into the airbox (I think). This means the turbo spins down during engine braking and will need to be spun up again when you open the throttle. I'm sure the trick twin turbo setup on the D4 has something to mitigate this though.

 

[pure_driver]

I was considering to swap my 278mm front discs in favour of the 300mm version, so I started looking for parts when I managed to find an used set of calipers and mounting brakets coming from a Focus ST with 320mm discs. The price is good so I'm tempted to switch to the "big" version.

I've read in another forum about Volvo C30 users having made succesfully the same swap, from to 278mm to 320mm, plus fitting the Focus ST calipers and brakets.

My doubt is if the standard V40 16" ET50 wheels (used for winter tyres) will clear the 320 calipers. I managed to find some info on a US Focus forum, with some statements about a 16" wheel capable to clear such 320mm calipers.

My other concern is that the ABS system with oem 278mm discs is calibrated on such size, does someone knows if with a 320mm disc set there could be any issues?

@buzby: have you encountered any strange behaviour with the ABS after fitting the 300mm discs?

Thanks to all.

 

[buzby]

@buzby: have you encountered any strange behaviour with the ABS after fitting the 300mm discs?

No issues experienced with the ABS system. It usually works on feedback - it applies the brakes until it detects that a wheel has locked, releases them and then applies them again until it no longer detects locking (it does this by monitoring the speed reading of all 4 wheels).

The only thing I have found with the 300mm discs is that when the car is light it has a tendency to 'grab' the brakes when braking on poor surfaces. It just took a bit of getting used to and adjusting the amount of force I use when pressing the pedal

The 320mm brake upgrade would probably be a bit much on a car that was specced with 278mm from the factory. It requires a new set of hoses and bleeding the brake system (and if I was using second hand calipers I'd want to inspect and rebuild them before putting them on the car). The 300mm swap is far simpler as it's only the discs and caliper brackets that need to change, and the performance is more than adequate

 

[pure_driver]

Thank you for your feedback!

Yes, I agree with you about second hand calipers being serviced prior to be fitted on the car. As written I found an used set at good price, but I still need to have a quote for the revision work. Let's see...

Probably the 300mm discs will be enough for my V40 D2 powered. Rather I'd also fit a set (front/rear) of steel braided brake lines, this is a mod I performed on my other past cars and I found it very useful.

I contacted both Hel and Goodridge in UK but none of them at the moment are producing a kit for the current V40 model. It's a pity because they have plenty of Volvo kits... I don't know if the C30 or the V50 versions will fit.

Hel offered me to build a "custom" kit but they need a specimen to make it as they do not have any info on oem size. Do you know of any other companies offering a "ready" kit for the V40?

About the "grab" feeling, are you referring to the fact when you touch the brakes they react in a stronger way than they should normally? Could it be because the new pads have a greater surface contact area with the 300mm discs?

On the local italian Volvo forum, some V40 CC users with 320mm discs, "complains" about such behaviour because they can drive both 300mm and 320mm equipped V40s, they say that the 320mm discs provide a great stopping power and they need to gentle press the brake pedal to avoid any "grabbing". Yet they also say the 300mm discs are a bit "weak". This last sounds a bit strange to me, maybe they get used to the bigger ones.

 

[hullu]

Hei HydraC,

Just looking at Motonet Finland, then noticed prices per disc, not the pair, never seen that before. Bilteema used to do everything Volvo did you have any luck there with parts?

 

[kevinlufc]

How easy is it to change the front pads on the Volvo? I am considering having a go myself. It's been yearssssss since I last changed pads on any car.

And what would be considered a good price for pads?

 

[buzby]

About the "grab" feeling, are you referring to the fact when you touch the brakes they react in a stronger way than they should normally? Could it be because the new pads have a greater surface contact area with the 300mm discs?

The 'grabbing' in some conditions is becuase the large brakes have more bite and less fade (there is more metal to sink the heat into). It just takes a little while to adjust the amount of pedal pressure required in certain road conditions. The pads for the 278mm and 300mm discs are identical..

On the local italian Volvo forum, some V40 CC users with 320mm discs, "complains" about such behaviour because they can drive both 300mm and 320mm equipped V40s, they say that the 320mm discs provide a great stopping power and they need to gentle press the brake pedal to avoid any "grabbing". Yet they also say the 300mm discs are a bit "weak". This last sounds a bit strange to me, maybe they get used to the bigger ones.

Unless you are taking the V40 on a track the 300mm brakes are more than adequate for a D2, especially as it's the lightest version fo the V40 (to get it into the under i00mg CO2 tax bracket).

The 320mm brakes would be over-powered on the D2, and in cold weather in particular you would probably get much worse performance - the larger pads will put less heat into the disc, and the larger disc will dissipate what heat there is faster.

How easy is it to change the front pads on the Volvo? I am considering having a go myself. It's been yearssssss since I last changed pads on any car.

And what would be considered a good price for pads?

A pair of long nose pliers to remove the retaining spring, a 7mm allen key or bit for your socket set to remove the caliper slider bolts, a wire brush, some copper grease, a bent coathanger to hang the caliper off the suspension spring while you work and and a caliper windback tool. The hardest bit is usually getting the alloy wheel off as it's usually corroded onto the steel hub centre. It's about £40 for a set of genuine Volvo pads, less if you go for an OEM set from ATE.

 

[chiptivo]

Am I being stupid here, but I've just read the pads are the same size on the 300 discs??
Surly the breaking will be exactly the same and there is no point?

 

[buzby]

Am I being stupid here, but I've just read the pads are the same size on the 300 discs??
Surly the breaking will be exactly the same and there is no point?

The bigger disc sinks more heat so they are less prone to fade. The further out from the centre of the wheel the pad acts also increases the braking power.

 

[pure_driver]

I contacted both Hel and Goodridge in UK but none of them at the moment are producing a kit for the current V40 model. It's a pity because they have plenty of Volvo kits... I don't know if the C30 or the V50 versions will fit.

I'm quoting myself as I was able to find a kit made by Goodridge; strangely it's not available in the official UK catalogue or at least their site is not updated but they produce a kit for the V40 II.

@buzby: thanks for the other info!

 

[Coby]

So much info and I've had a quick browse but anyy specific tools needed to change front pads or is it just rears that need a windback tool?

 

[buzby]

So much info and I've had a quick browse but anyy specific tools needed to change front pads or is it just rears that need a windback tool?

You can just about get away with a block of woods and a g-clamp on the front calipers, but a windback tool makes the job a lot easier and is less likely to cause any damage to the piston seals or bores. Apart from that, a 7mm hex key (or socket for a ratchet drive) and a pair of long-nosed pliers are all you need, and a suitable rubber pad for your jack to avoid damaging the chassis.

 

[Porterpainter]

Thanks to all, especially @buzby for all the great info on this thread.

I have one question - is there a need to remove the cap on the brake fluid reservoir, or even remove some fluid, before retracting the calipers?

 

[buzby]

Thanks to all, especially @buzby for all the great info on this thread.

I have one question - is there a need to remove the cap on the brake fluid reservoir, or even remove some fluid, before retracting the calipers?

It's a good idea to loosen the cap. You shouldn't have to remove any fluid unless the fluid has beenv changed since new pads were fitted (if the reservior was filled to the top when part-worn pads were fitted, winding the calipers back could lead to an overflow)..

 

[Tony1]

The front discs and pads on my D2 R Design are ready for replacement. I don't want to change the calipers to get 300mm discs, so I was wondering if grooved, drilled or dimpled discs (or even a combination) would improve braking action.


Would grooves etc make much of a difference to noise, I've heard both yes and no answers in the past.


Thanks for your help

 

[Kristianstad_2]

For winding the rear pistons back in:
Would inserting a set of needle pliers in the two holes work? Or it is going to work only with the specific tool?
I guess that we should open the container where the brake liquid is to release some pressure when winding back the piston?

 

[buzby]

Would grooves etc make much of a difference to noise, I've heard both yes and no answers in the past.

Grooved discs are definitely noisier, especially under had braking (they can also transmit a pulsing vibration back up the pedal too).It depends on the pattern, number of grooves and the depth though. When I've used them in the past I've also found they have a greater tendency to warp after repeated heavy braking too due to grooves affecting the expansion rate of the metal).

For winding the rear pistons back in:
Would inserting a set of needle pliers in the two holes work? Or it is going to work only with the specific tool?
I guess that we should open the container where the brake liquid is to release some pressure when winding back the piston?

You have to turn and press the piston in simultaneously, which is difficult to do with pliers (the shape of the caliper also makes access difficult). It's far easier with a windback tool, and they aren't that expensive.

Yes, it's a good idea to open the brake reservoir cap (and put a rag around it just in case it overflows). It's more of an issue if the fluid has bee nchanged to topped up since the car left the factory.

 

[Kristianstad_2]

Sorry if it was already mentioned, but should the tool be right or left winding?