11 replies to this topic

[M700FGT]

Hi all,

Just gone to change the V belt on my 97 Cooper mpi.

The old belt was a Dayco 5pk935 - the new one is a 5pk925.

Everything online says its the 925, but it’s shorter and won’t fit.

The 935 fits perfectly, but according to part shops online, the 935 doesn’t fit Mini’s at all.

Anyone else had this issue?

What would cause this change?

Many thanks

[panky]

Maybe a larger diameter water pump pulley has been fitted.

Have you tried removing the adjuster bracket completely, might give a bit more room to get the new belt on.

Edited by panky, 23 September 2018 - 12:13 PM.

[Bat]

Hi,

MPI belts are difficult to get on, maybe someone fitted the longer one for that reason.

I undid the adjuster bolt all the way then slackened the pulley clamping bolt off so it was only just hanging on then fit the belt.

Cheers 

[Steve220]

As above, needs to be slackened right the way out. 925 is the correct one.

[Wiggy]

I normally locate the belt on all the pulleys except the alternator. Then with a but of force pop as much of the belt as you can on the alternator pulley. Then turn the pulleys and the belt should walk itself onto the alternator pulley fully.

Edited by Wiggy, 23 September 2018 - 01:25 PM.

[Dusky]

Well if the 935 works,and is easier to fit, why arent you getting a new one like that? Unless competing in a concours i wouldnt bother that much about originality...

[M700FGT]

Hi guys, thanks for all the comments.

 

I will have another look, but the 935 is really tight and seems to fit perfect. Im happy to leave it on, but just wanted to know why it was on there in the first place.  

 

I was only replacing it as i didn't trust the previous owner, so i have been replacing all the service items like this so that i know they are good.

 

 

Has anyone got a user guide / instructions (other then Haynes) just encase i have missed anything. 

[Wiggy]

User guide / instructions with regard to what?

Haynes is as good as anything regarding basic servicing.

[croc7]

You don’t want the fan belt to be tight as a banjo string. Haynes manual says it should have 13 mm of belt deflection midway between the crankshaft and alternator pulley. Otherwise it could result in too much strain on water pump or alternator bearings.

[timmy850]

The only difference between the two is 10mm, or about 1% difference in overall length. It might have been the only belt in stock at the time when the previous owner changed it, or perhaps it was recommended to them as it's easier to fit. 

[M700FGT]

Thanks all. I will have another look at it over the weekend. The 935 seems to be a perfect fit, but I will have another play just encase.

As for instructions, I was thinking something a bit more detailed then Haynes with photos.

[germini30]

You will probably find the new number could be 5pk938.only 3mm longer than yours