[essex_lad]

Hi guys a year ago I fitted front 335 brakes to my 325 with no issues, I have just fitted 335 rear breaks and after manual and pressure bleeding my brake pedal just has so much travel before I get decent brake pressure. Do I need a 335 master cylinder or is there something I haven't done?

[kimoboy]

I think you will need bigger master.

[R99]

Can't see you needing a bigger master cylinder!

More likely to have air in the ABS unit? If you have it will need to be bled using INPA at BMW, or at a specialist with the software

[R99]

A quick check on the ETK reveals 325 has the same master cylinder as the 335.

So there is no requirement for any master cylinder upgrade. My 325d ran the BMWP 6 pots / 2 pots with no master cylinder upgrade

It now runs F3x 4 pots fronts with 370mm discs and stock single pot rears with 336mm discs (same rears as the 335) - again with no issues!!

I highly suspect you have air trapped somewhere!!

I'm sure they are, but have you made sure the new rears are fitted the right way round?? My rears were fitted with the bleed nipples at the bottom by a local garage, and the system could not be bled properly! (Long story, but pretty shocking!)

[essex_lad]

Originally Posted by R99

A quick check on the ETK reveals 325 has the same master cylinder as the 335.

So there is no requirement for any master cylinder upgrade. My 325d ran the BMWP 6 pots / 2 pots with no master cylinder upgrade

It now runs F3x 4 pots fronts with 370mm discs and stock single pot rears with 336mm discs (same rears as the 335) - again with no issues!!

I highly suspect you have air trapped somewhere!!

I'm sure they are, but have you made sure the new rears are fitted the right way round?? My rears were fitted with the bleed nipples at the bottom by a local garage, and the system could not be bled properly! (Long story, but pretty shocking!)

To be honest I'm not sure if it's the correct way around both calipers seem to be the same so one has the nipple at the top and the other at the bottom.

The garage that done the pressure bleed was just a tyre fitting garage so I really doubt they used inpa to release air from the abs tbh. I have a 325I so I'm not sure if it is different but if you can run them bad boy calipers off your master then I should have no issues.

[R99]

325i has the same master cylinder as my 325d!

I think it's air in the system, combined with the fact that one caliper has its bleed nipple at the bottom.

I'm no mechanical expert mind, just going off previous experience!

I got my car taken to BMW who refitted my rear brakes correctly with the bleed nipples at the top & pressure bled the full system, including the ABS unit using INPA to release any trapped air.

Expensive mistake by the original garage as they had to cough up! Works like a dream now!

[RajB]

I've had this when going to BBK's previously. When removing the rear to swap them out they've allowed them to bleed out and this causes the system to lock off the rears through the ABS unit. You need to cycle the system and properly bleed again using the correct software.

I'm running Alcon's now on my 335i and no issues at all.

[Aragorn30d]

Originally Posted by essex_lad

To be honest I'm not sure if it's the correct way around both calipers seem to be the same so one has the nipple at the top and the other at the bottom.

Thats not right... The calipers should both have nipples at the top, thye are sided.

Sounds like you have two calipers from one side.

Its impossible to bleed as the air just sits in the top of the piston.

[RajB]

Originally Posted by essex_lad

To be honest I'm not sure if it's the correct way around both calipers seem to be the same so one has the nipple at the top and the other at the bottom.

Missed this post from you but as others have said that is definitely not correct. Tbh the garage fitting them should know this too so I really wouldn't trust a mechanic to be able to bleed the system if they don't even realise the caliper is not correct and fit it that way.

[essex_lad]

Originally Posted by R99

325i has the same master cylinder as my 325d!

I think it's air in the system, combined with the fact that one caliper has its bleed nipple at the bottom.

I'm no mechanical expert mind, just going off previous experience!

I got my car taken to BMW who refitted my rear brakes correctly with the bleed nipples at the top & pressure bled the full system, including the ABS unit using INPA to release any trapped air.

Expensive mistake by the original garage as they had to cough up! Works like a dream now!

I fitted the brakes myself but the garage did do the pressure bleed. Im taking it back there again tonight to let them have another go at it. If they cant do it shal I ask for my money back?

[R99]

Originally Posted by essex_lad

I fitted the brakes myself but the garage did do the pressure bleed. Im taking it back there again tonight to let them have another go at it. If they cant do it shal I ask for my money back?

Its a grey area really mate, as with you fitting the brakes yourself, there is a possibility that air has got into the ABS pump via the lines being undone to the calipers. Did you clamp the hoses off, as my understanding is that they must be clamped off?

The garage will never in a million years be able to get the brake pedal back if the above is the case!

Also, you need to get to the bottom of the fact that only one of your rear calipers has its bleed nipple in the correct place. Did you buy your rears from a breakers yard?

I'd be asking for a new rear to be sent out to you - swap it over and then get the car pressure bled at BMW using INPA to remove air from the master cylinder / abs pump / dtc unit.

Might cost £100 or so, but will 100% fix the issue.

The only other suggestion is to make sure you have no brake fluid leaking from the lines or bleed nipples - that could also be causing a soft pedal.

[essex_lad]

Originally Posted by RajB

I've had this when going to BBK's previously. When removing the rear to swap them out they've allowed them to bleed out and this causes the system to lock off the rears through the ABS unit. You need to cycle the system and properly bleed again using the correct software.

I'm running Alcon's now on my 335i and no issues at all.

Ok looks like air is to blame and incorrect bleeding. Now i just need to find a garage that can do it. BMW are quoting next week and to be honest its dangerous.

[essex_lad]

Originally Posted by Aragorn30d

Thats not right... The calipers should both have nipples at the top, thye are sided.

Sounds like you have two calipers from one side.

Its impossible to bleed as the air just sits in the top of the piston.

They have different part number's, Could i not take off the caliper and flip it around for bleeding then once done put it back on?

[Aragorn30d]

Maybe they've supplied the wrong part then?

Air rises to the top, so the bleed nipple has to be at the top for it to work.

You could try removing it from the hub and turn it over to bleed it, but surely the proper job is to get the correct caliper with the nipple at the top where it should be...

I fitted 330d calipers to my brothers 320d. I did nothing fancy just unbolted the old ones and bolted the new ones on. So long as the reservoir remains full of fluid, gravity will have ensured no air went back up the way, and there should be no need to bleed the ABS unit. On his car we manually bled each corner, oldskool footpedal style, and job done.

[essex_lad]

Originally Posted by R99

Its a grey area really mate, as with you fitting the brakes yourself, there is a possibility that air has got into the ABS pump via the lines being undone to the calipers. Did you clamp the hoses off, as my understanding is that they must be clamped off?

The garage will never in a million years be able to get the brake pedal back if the above is the case!

Also, you need to get to the bottom of the fact that only one of your rear calipers has its bleed nipple in the correct place. Did you buy your rears from a breakers yard?

I'd be asking for a new rear to be sent out to you - swap it over and then get the car pressure bled at BMW using INPA to remove air from the master cylinder / abs pump / dtc unit.

Might cost £100 or so, but will 100% fix the issue.

The only other suggestion is to make sure you have no brake fluid leaking from the lines or bleed nipples - that could also be causing a soft pedal.

Yer i bought them off the breakers as a pair, i did find it odd one nipple was facing down. I have just ordered another one as i bought these a year ago. ill just put one on ebay.

I did clamp the line but maybe not well enough as fluid did still drip out. I will change the caliper and put it into BMW, get it done properly. Sadly this is getting expensive.

[RajB]

Originally Posted by essex_lad

Yer i bought them off the breakers as a pair, i did find it odd one nipple was facing down. I have just ordered another one as i bought these a year ago. ill just put one on ebay.

I did clamp the line but maybe not well enough as fluid did still drip out. I will change the caliper and put it into BMW, get it done properly. Sadly this is getting expensive.

Strange they are different part numbers as it certainly suggests you have 2 same sided calipers.

Unfortunately these things do happen when buying from the likes of breakers.

[essex_lad]

Originally Posted by RajB

Strange they are different part numbers as it certainly suggests you have 2 same sided calipers.

Unfortunately these things do happen when buying from the likes of breakers.

I know, they do my head in.

[essex_lad]

So the garage refunded me. I made the point that I paid for it to be bled properly and it hasn't been. The company should train their staff on all these different cars.

[AzRiz]

No offence but it is not the garage's fault that they couldn't bleed a setup that is completely incorrect...you have one upside down caliper with the bleed nipple at the bottom??? Man that is so bad...you really need to sort that issue out ASAP. Bleed nipples must always be at the top.

[essex_lad]

Originally Posted by AzRiz

No offence but it is not the garage's fault that they couldn't bleed a setup that is completely incorrect...you have one upside down caliper with the bleed nipple at the bottom??? Man that is so bad...you really need to sort that issue out ASAP. Bleed nipples must always be at the top.

Yes I know. Still even if it was the correct way they wouldnt be able to bleed the car because they dont have the correct equipment to do it so really they should say they cant do it.

The garage even took the caliper off yesterday and turnt it around with a pack between the pads the same size as the disc and they were still unable to do it.

[AzRiz]

Originally Posted by essex_lad

Yes I know. Still even if it was the correct way they wouldnt be able to bleed the car because they dont have the correct equipment to do it so really they should say they cant do it.

Fair enough. To even entertain the idea of bleeding an upside-down caliper was a weird decision on their part.

[essex_lad]

Originally Posted by AzRiz

Fair enough. To even entertain the idea of bleeding an upside-down caliper was a weird decision on their part.

They are only a glorified tyre fitters really to be fair,cant expect too much.