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Vito 280 ,ZX7r,gsxr 750, ,Z650 Cafe ,Benelli Tornado.Ford consul , Ford Pop , ,Chevy Astro,Dog,Wife
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Discussion Starter #1
Long story short..Van tested , commented that rear brake efficiency was at its limit, i.e not enough ,get looked at .....Now ,i'm under the van at the back ,theres some sort of device that the lines go into, a lever action connected mechanically by a spring to a bar connected to the rear swing arms...the adjustment nut is just at its limit of thread...took bracket off to get a better view and find when you apply the brakes it gives a short pulse if pressure is made against the lever...Does this valve thingy control the pressure to the rear brakes or should i be looking somewhere else.....URGENT..van is on axle stands.....HELP
 

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Vito 112 CDi year:2001
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Few questions..
I'm guessing your van is coil springs rather than pneumatic.
You had an mot test on the van?
When they said the rear brake efficiency was at its limit. They meant they rear caliper brakes, or the hand brake that works on the rear wheels?
What thickness are your pads on the rear? The minimum is 2mm.
When did you last change the brake fluid? (every 2 years)

It could be the brakes need bleeding at the rear.

The device with lever you mention is the brake pressure regulator. Other than making sure the spring hasn't rusted off I don't think you adjust this. Russek makes no mention of this.

I would bleed your rear brakes first. You could also go as far as removing the pads and spraying some brake cleaner on the discs (are they completely rust free on the braking surface?). Although you may have to push the pistons back to get the pads back on again. Use a g clamp and a block of wood.
 

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Vito 280 ,ZX7r,gsxr 750, ,Z650 Cafe ,Benelli Tornado.Ford consul , Ford Pop , ,Chevy Astro,Dog,Wife
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Discussion Starter #3 (Edited)
Thanx mate, did all you mention, pads are about 75% good, took off calipers ,cleaned everything ,bled the rear....the brakes were always a bit spongy, e.g if you keep your foot on them long enough the pedal will go to the floor, i assume this is just the vacuum as another van i tried did exactly the same...Do you know why this regulator is connected to the suspension, and why it would need to be adjustable.When the pedal it pressed theres a small pulse that pushes against the lever, but it does it only once when you press the pedal..to me the brakes are fine ,they havent deteriorated at all..or maybe i'm just use to them.
 

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Vito 112 CDi year:2001
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My grasp of the regulator is that it splits the braking force between front and rear brakes. You don't want the same braking force on the rear as the front otherwise they would lock up. I don't know what the % difference in force is between front and rear. Its connected to the suspension as a way of adjusting the braking force to the rear calipers as the load in the van changes. The more load in the the van, the more braking force in relation to the front brakes can be applied before the rear brakes lock up.

Spongy brakes are a sure sign of air in the brake lines. You'll get this if the brakes weren't bleed properly last time the fluid was changed. This is a possible reason for your poor rear brakes. Why do you think its the regulator?

The brake pedal going to the floor - is this with the engine on?

Who's the tester that pointed out the brakes in the first place? mot?
 

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Spongy pedal = air in brake lines; pedal to floor = either leak in system or brake master cylinder kit renewal.
Did brake pedal floor before you tinkered with system? Check all bleed valves properly for tightness.
 

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08 115CDi, 99 A4 1.8T, 98 ZX9R, 84 GPz1100, 76 Range Rover 2dr.
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Hi GixxerPat
4Xpaws is spot on with his understanding of the pressure regulator at the rear of your van. Without it when the van is empty it would be almost unstoppable as the back wheels would just lock up. Think of stamping on the rear brake pedal of the GSX R.
I would agree with Punjabi's air in the system, old fluid, or deteriorated seals, cracked / split hoses or internally collapsed flexable hose . On the non ABS CDi the circuits are split front left/ rear right and front right / rear left. Each circuit should be bleed in turn starting with the rear then the corisponding front. i.e rear right then front left , rear left then front right.
Should this sequence is the same with the non-CDi 108 you have.
Overall I would say with brakes if it looks slightly suspect replace it before it fails, a Vito should stop reasonably well, there is never much feedback but they should not be spongy.

Regards

ZX9
 

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Vito 280 ,ZX7r,gsxr 750, ,Z650 Cafe ,Benelli Tornado.Ford consul , Ford Pop , ,Chevy Astro,Dog,Wife
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Discussion Starter #7
MMMM..zeeX niner...rear wheel steering....dont ya just love it..lol..Going to start afresh..bleed the whole system as 4x says, the fluid's probably been there since..1997...i'll tell you the outcome just in case it helps....might be handy if we had a proper TECH section here...Tanx for all the help guyzzzzz..Pat.
 

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me old biker mates, for what its worth, my 115 has always (from new) had a brake pedal that acts as you describe " if u hold your foot down long enough, the pedal goes all the way down" but if you stamp on the brakes, you WILL go through the windscreen if you were moving. Techy at merc told me its normal , had something to do with the ABS, also suggested that after a brake pad change, I should get the ABS to activate a couple of times (I drove it on wet grass and stamped on the brakes) which did improve pedal feel after changing front pads - very odd hydraulic system this.
Oh, and the carsoft diagnostic software also gives you an option to actuate the ABS to each wheel seperately and me thinks this is related to this whole issue.
 

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oh, since we are talking bikes, I am off to a track day in the morning, should freeze my nuts off in the morning!!
And if u think your rear brakes are shite, try the one standard on an Aprilia, proper fish bicycle!!
 

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Discussion Starter #10
Italian muck...lol....Casey stoner wins again!!.....Cant wait to do a tracky again , have a track zx7r ex race....wish i had THOSE brakes on the van.!!
 

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I see what you mean about the pedal sinking to the floor if you push long enough. Never noticed it until you pointed it out. I wouldn't call this spongy though. The last bit of travel of the pedal I hear a sound similar to air leaving a bellows coming from passenger side and if you pump the pedal it sounds like a lilo's being inflated somewhere under the bonnet.

I 've had a master cylinder fail on an old car, I would put my foot on the pedal and there'd be nothing there, put my foot again and its back to normal. Not the sort of fault you can drive around with.
 
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