Fix leaky external kitchen sink pipe

[piranha86]

Hi,
I am a novice DIY-er and was wondering how I can fix this external kitchen sink pipe that goes to the drain (see pictures). The 90 degree attached to the wall has cracked and the joint is held with some kind of silicone material. The joint comes off completely sometimes and needs to be put back and is also leaky. If I want to fix the cracked 90-degree pipe, do I break into the wall and install one of these below and then re-plaster it?

FloPlast Conversion Bends 90° White 40mm 5 Pack - Screwfix

Order online at Screwfix.com. 40mm 90° bend. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

Also, for some temporary relief, how do I make sure the joint doesn't come off? Does anyone know what this silicone material is called?

 

[Madrab]

Push fit ... was never designed to be exposed to the elements. The solvent weld elbow won't fit or be glued as it's a different size and material. Compression is the only way, or a new push fit and paint them both.
The pipe won't be far behind it, nor the other waste fittings below it or on the other waste pipe. Might be an ideal to replace it all as it will cause problems in the future.

 

[piranha86]

Thanks for the prompt reply and your help! Do you mean the elbow joint should come off without me disturbing the external wall? Apologies, I am a bit of a novice, what is compression? Attaching some pictures of the inside

 

[Madrab]

First off, the connection onto the sink waste looks like it's cross threaded and it's been leaking, so that might need replaced.

The external elbow is just pushed onto the pipe that's running through and will be sticking out the wall, so it will just pull off. Unfortunately though you may have to chip some of the mortar away as it looks like some of the elbow has been embedded into it. Then you can use a compression elbow to replace it - one of these - (or another pushfit if no other option)