Advice - broke a vacuum hose in a difficult place!

[haymitch]

I've recently been trying to solve a hot start problem that developed out of another thread I've posted here:

https://www.volvoforums.org.uk/showthread.php?t=288169

I've cleaned the IAC and MAF sensor. Whilst cleaning the IAC I found the connecting hoses have split so replaced them with some silicon hoses.
I broke a vacuum hose whilst replacing the Idle air valve hoses. The vacuum hose I broke must have been near to breaking anyway as the remains are very crumbly! Could some give me some advice on replacing this please? I have a few questions:

1) What internal diameter are the vacuum hoses on the Volvo 940 2.3 LPT? I've uploaded a photo of the two connections of the vacuum hose. Including the broken end circled in red. I measured one side and it was 4mm and the other and it was 5mm.
2) Which components are the vacuum hose connecting?
3) What is the best plan of attack for replacing the vacuum hose? I plan to remove the air pipe to the throttle body and maybe the IAC so give me more room to place with. I don't feel confident removing the whole throttle body itself just yet - that's a future project!

Here's an image of the broken vacuum hose and its connections. Excuse the lack of hose clamps on the IAC hoses, I'm going to add these later because partsforvolvos sent me the wrong ones

https://imgur.com/a/obNAXYB

The car still starts and struggles to hold an idle (unsurprisingly). Interestingly, the symptoms are very similar to my previous problems albeit a lot worse.

[Forrest]

I think the internal diameter of those hoses is nominally 4.5mm. Volvo OEM part number is 976734 and it is sold by the metre. I have always used genuine Volvo replacement because it is supposed to be heat proof. Cheaper third-party replacement might not be.

It is not clear to me which line is broken. Possibly the vacuum to the oil trap. They do go very brittle. If that is the case your best bet is to disconnect the two wider hoses as well and remove from the depths of the inlet manifold the plastic y-piece to which that small hose connects. It will probably need carbon deposits removed from it before reassembly.

If you do decide to remove the idle control valve and/or the throttle body for access both are very easy to remove but to reinstall the throttle body you will need a new paper gasket.

[mike1950]

Hi,
Have 940 2.3 LPT.
Same problem replaced these 2 hoses yesterday.
The broken hose is the top one coming from the right wing and the lower hose goes across to a T piece coming up from beneath and accessible behind the inlet manifold?

There was no need to dismantle anything .
Went in from bulkhead side with right hand and twisted the clamp around with my fingers to turn the 3 horns to the rear then a pair of pliers to pull them together. With left hand coming under from the front eased off the old hose
Loosely fitted new cable ties to route and threaded through hoses.New clamp fitted to hose and pushed up an inch,left hand to fit on hose and orientate horns to rear.Right hand from rear with pliers and bring clamp down hose.

[Laird Scooby]

Not sure where the hoses are broken from your pics or what the components are they are connected to (one of those things where the surroundings would give a big clue rather than the stub on the end of something that can't be seen easily) but Mike1950 above seems to recognise them from very recently replacing his.

Whichever way you look at it, it's going to upset the starting and idling having a vacuum leak.

Good luck getting it sorted anyway!

[mhuk]

Ebay silicon hose will do the job. 4mm IMO. Oddly enough I snapped a tee piece on Sunday. Lucky I had a spare though.

https://www.ebay.co.uk/sch/i.html?_s...um+hose&_frs=1

[haymitch]

Thanks - that's all really useful! I'll give the Volvo parts department a call and see if they have some OEM hose. I haven't had much luck finding it online without a high price or long wait time.

Otherwise I'll give the silicone a a try

[Laird Scooby]

Originally Posted by haymitch

Thanks - that's all really useful! I'll give the Volvo parts department a call and see if they have some OEM hose. I haven't had much luck finding it online without a high price or long wait time.

Otherwise I'll give the silicone a a try

As a temporary measure, you may find there's enough length on the existing hose to snip the perished end off and reconnect it where it should be - slight re-routing might be needed to gain the extra inch or so to get it to reach but it will get you going until the replacement hose lands.

[Rversteeg]

Use a hose clamp if possible to take the tension off from the hose where it is stretched over the pillar. Worked well for my tired cruise control vacuum hose which was getting shorter and shorter from my cutting it every time it split again...

[baggy798]

It's the valve that controls the EGR valve, which has more than likely seized up anyway. 4mm silicone hose will be fine.

976734 comes up as £15 a metre?!

[Laird Scooby]

At least Volvo have done the sensible thing and mounted the EGR valve remotely and not on the exhausst manifold like many manufacturers do.