Hi Audi community!

I'm having trouble identifying this cracked hose on my 2010 Audi q7 3.6. I'm not sure of the part number and need help replacing it.

Does anyone know what this hose is and where I can find a replacement part?

 

It appears to be the vacuum hose to the brake booster. Did you notice anything with your brake feel?

 

Thanks for the suggestion! I may have noticed a slight difference in brake feel, but I stopped driving the car after finding the crack. The car was driving very rough. Is there an easy way to confirm it's the brake booster hose myself? And if it is, do you know the part number? I'd like to try and replace it myself if possible.

 

If it is the brake booster vacuum hose the brake pedal will be very hard and the braking weak with the hose fully disconnected. Plugging or capping the open hose barb should smooth out the rough running too. Sorry I can’t identify the hose from the photos . On my TT roadster I have had a brake boost hose split like that where it connects to the brake booster check valve. Similar looking arrangement. Hose is an assembly of hard plastic tubing with that flexible hose ( that splits) at each end. Can you trace the split hose to where it goes? Might replace it with generic reinforced rubber hose. That’s what I did on the TT.

 

YES, that is 100% the female connector end of the brake booster vacuum hose where it meets the engine's vacuum hose line. You can fairly easily DIY a repair on that cracked end, or go further back on the hose line to splice into it, or buy a brand new vacuum hose to the brake booster. Wait till you see how much they want for one of those hoses, lol.

Mine cracked a lot worse than yours looks...more like a flower petals effect, and I just removed the engine (male connector) from it, then used some strips of 100mph tape to reform/reinforce shape, reinserted male connector, then went back over the entire connection from the firewall entry point to past the engine vacuum line to make it airtight. No issues since then. Your engine runs like crap because of the vacuum leak, which impacts myriad other systems and feedback loops on these cars. You may or not have noticed any significant drop off in braking with a crack like yours has in it; mine was much worse than that, and I was having braking issues, but it's not as cut-n-dried as folks on here think....a soft, low brake pedal was the primary symptom.

I looked up the part to see if I could find a deal on it...not something I would buy a used part on as they all crack like this from heat cycling in engine bay. When I saw the price I decided to fix it myself using what I had at home. You can also use pipe-repair specialty tapes that harden like epoxy after application, etc., but I just kept it simple.

 

Thanks for confirming it's the brake booster vacuum hose connector and for all the advice! I appreciate you sharing your experience with a similar (or worse!) crack. I'm definitely going to try the DIY repair route first. I might also look into those epoxy-like pipe repair tapes you mentioned for extra reinforcement. I have no experience with hoses or pipe repair. Is this the kind of tape you are referring to:
It looks promising. It's reassuring to know that a fix is possible.

Thanks again for the detailed explanation and tips!

 

These forums are all about DIY fixes.
That said, I will also provide word of caution:

It can definitely be repaired as it only carries vacuum pressure, and the male fitting reinforces interior of the cracked female fitting, etc., but it's just about being very, very, very careful and using the right sized/type of materials to ensure a tight air seal results, as we are talking about your brakes here, and this vacuum line connection to the brake booster is what gives gives you 'power assisted brakes' rather than you sticking your foot down through the floorboard like Fred Flintstone and hoping to stop this beast.

As was mentioned by other forum members, there are a couple diff methods you can use to resolve the cracked fitting end. Wrapping the end back up and reinforcing the connection point is just one option, albeit the simplest. Just be mindful that material is heat-stressed and somewhat fragile, and the wrap needs to start close to the firewall opening where it passes through to help contain any future spread of the crack.

Whatever option you choose, the repair must be heat-resistant, durable, and form an air-tight seal to stop the vacuum from escaping that line. If you do use the wrap/reinforce sealing method, it's quite likely it will require a proper 'splice' type repair at some future point, to be able to cut into that vacuum line behind the firewall partition, where the integrity of the line is better protected from the engine heat, etc.

Overall, this isn't even close to rocket science DIY skills that we are talking about here, but your safety, and that of your family members and others, etc., depends on the quality of this repair.

 

should be this

 

I think this is the male part, I need the female

 

It's the correct part (vac hose to/from the brake booster), there's just different versions of that hose, as illustrated, depending on what engine you got and whether car is RHD or LHD market.

Frustratingly, you'll find that the hand drawn illustrations used by VW/Audi for parts representations are generally not great on their clarity and ratios to the actual part, although this diagram isn't bad. Note though that it is clearly detailing how it connects directly to the brake booster, so that's your clue-in, and then the detailed written description gives you the engine each listed part diagram matches up to, etc.

Just as reference, the 'male' hose from the engine side are shown in the right hand side, lower of that diagram, etc.