Bongo Fury

Morning all, I hope someone is able to assist with an issue I am having.

A few weeks ago, my van over heated whilst out on a sunny Sunday drive. The issue was that both of my alternator belts (which I hadn't changed as per the maintenance schedule ) had failed, meaning the water pump had ceased to operate....

To cut a long story short, I purchased new belts, fitted them, had the van fully serviced and checked over, and was driving the van for about a week, when I thought I'd take a little look under the bonnet/passenger seat...

One of the (brand new) alternator belts had turned itself inside out, but was still nestled in the v-groove of the pulleys. There was some damage to this belt and due to some rubbing, had also affected the other belt. Suffice to say, I stopped using the van before one or both failed again, and am now seeking help.

I believe that the belt inverted itself because I hadn't tightened the tensioner bolt sufficiently; however, this brings me to the reason for today's post/question: I can tighten the tensioner bolt until it is virtually at the end of it's run, i.e. the alternator is pulled fully towards to the passenger-side of the van.

I had noticed this previously after changing the alternator some time ago, but since no problems were being caused, I thought nothing of it. But now, with these recent problems, I am starting to question this. Shouldn't the tensioner bolt, when fully tensioned, be more central on the 'run'?

To this end, I have just ordered two 13x1050 and two 13x1075 v-belts (instead of the standard 13x1100 belts) from eBay to see if these will fit, and allow me to tension the belts more fully, preventing them from inverting again.

Can anyone:
(a) Make sense of my rambling post?
(b) If yes, shed some light on this issue? I have searched long and hard for something similar on various forums, but with no luck.

Any advice/insight would be most welcome and greatly received.

Don't really understand your logic here.

This is the proper (toothed type) belt that your vehicle was produced with, unless someone has altered the mechanism / badly worn pulleys etc these are the belts for your vehicle..

Fitting the wrong type/size belts can cause damage to the WP/ALT/ harmonic damper/balance etc etc.

You also need to check that All the pulleys are In Line.


http://cn.oemol.com/oem/en_oem_detail/6 ... 381/*.html


Good Luck.

We are discussing the diesel engine? (Sorry if there are clues that are obvious to those that know!)

If anything, I found new belts tight to fit, even with the alternator fully in to the block.
Is it at all possible there is an incorrect pulley diameter, perhaps on the replacement water pump?

All the pulleys seem to be in line; there is a very (very) slight wobble on the water pump pully, but not enough to cause the belts to invert.

My point with the belt length is that I don't think I am able to fully tension the belts using the tensioner since it has reached the limit of the bolt. The 'nut' which the tensioner bolt threads through is almost touching the bracket. Hence, the belt is able to flip over.

What I was hoping for, was that someone else has had this problem and knew it was due to incorrect pulley sizes or something else which means that the belt therefore is too long, if you get my drift. If that was the case, I would then sort "that" (pulley or whatever) out and revert back to the standard 13x1100 belts, and all is right with the world.

In the absence of this, I am being forced into using slightly shorter belts, otherwise I could be potentially replacing the belts every few days or so.

However, maybe the tension bolt should be this far forward? I'm really not sure, hence this post, although it seems odd if it should. Could anyone let me know how far off the limit of the tension bracket is your tensioner bolt?

cmm303 wrote:We are discussing the diesel engine? (Sorry if there are clues that are obvious to those that know!)

If anything, I found new belts tight to fit, even with the alternator fully in to the block.
Is it at all possible there is an incorrect pulley diameter, perhaps on the replacement water pump?

I took so long to post my reply to Rita that you may have answered part of my query! I have never replaced the water pump, and my van was bought "off the boat" so to speak, so it might have been mis-replaced in Japan.

Btw, yes it is a diesel.

cmm303 wrote:We are discussing the diesel engine? (Sorry if there are clues that are obvious to those that know!)

If anything, I found new belts tight to fit, even with the alternator fully in to the block.
Is it at all possible there is an incorrect pulley diameter, perhaps on the replacement water pump?

A wee clue here....

" The issue was that both of my alternator belts"

Good Luck.

rita wrote:

cmm303 wrote:We are discussing the diesel engine? (Sorry if there are clues that are obvious to those that know!)

If anything, I found new belts tight to fit, even with the alternator fully in to the block.
Is it at all possible there is an incorrect pulley diameter, perhaps on the replacement water pump?

A wee clue here....

" The issue was that both of my alternator belts"

Good Luck.

ha! Thanks Rita. I did wonder but wasn't sure enough.

GowerOsprey wrote: ...
However, maybe the tension bolt should be this far forward? I'm really not sure, hence this post, although it seems odd if it should. Could anyone let me know how far off the limit of the tension bracket is your tensioner bolt?

I'll see if I've got any pics.
A/C belt right spec and tensioning up ok?

Have you measured the new belts
I had some a couple of months back that said 13x1100 but we're actually lots shorter
Came fron auto jap spares
And was a wrongly labeled batch

cmm303 wrote:

GowerOsprey wrote: ...
However, maybe the tension bolt should be this far forward? I'm really not sure, hence this post, although it seems odd if it should. Could anyone let me know how far off the limit of the tension bracket is your tensioner bolt?

I'll see if I've got any pics.

With belts of unknown age but virtually fell off once slack:


Taken for reference when taking off the alternator. Position of the pin isn't relevant to tensioning; I had just re-threaded it a little way.

the adjustment should be in the midrange of the bolt with the correct belts fitted, usually they are really hard to initially fit because they are so tight/small, they do loosen/wear in quite a bit early on though.
ive also had difficulty on several occasions getting the correct ones that are said to be a certain size when they are actually different. doesnt seem to be specific to one brand either.
i would also check the bottom pulley carefully, this is a rubber bonded jobby, they tend to become detached as in the outer pulley comes off the centre mount, this lets the pulley move forward and backwards along the crankshaft axis. to check, remove all the belts, with the bongo in park, try to turn the outer pulley by hand or lever it forward with a bar.look for rub marks on the front engine casing and swarf.

Thanks for all your replies and advice Rita, cmm303, Gasy and Northern Bongolow.

Plenty to consider and I will order some correct length belts from MazdaBongo.com to fit when I've sorted this out!

I tried to attach a photo to show you my tensioner bolt, but it won't let me, even after compressing the photo. (What is the maximum size image allowed on the board?)

GowerOsprey wrote:Thanks for all your replies and advice Rita, cmm303, Gasy and Northern Bongolow.

Plenty to consider and I will order some correct length belts from MazdaBongo.com to fit when I've sorted this out!

I tried to attach a photo to show you my tensioner bolt, but it won't let me, even after compressing the photo. (What is the maximum size image allowed on the board?)

Irrespective of what size belts you end up fitting they should be a matched pair(from the same batch) as there can be slight differences between cuts. That would mean that you would only be able to correctly tension to the shortest belt and the other would be looser possibly leading to the issue you describe.

And measure any new belts to make sure they are 1100
Good luck

Gasy wrote:And measure any new belts to make sure they are 1100
Good luck

Is that measurement round the outside of the belt or the inside?

Outside will do
Will let you know if your in the correct ball park at least