> Veitti Surti mæðit mjök, því hann sótti blóðrás ákafliga. 

> Surtr was made very exhausted, therefore a great
> hemorrhage overcame him. 

> Surt became very tired, (added to?) it severe hemorrhage
> overcame him.

Surt became very weary, for a severe hemorrhage assailed
him.

> Þess neytti Jökull ok brá Surti hælkrók, svá hann fell, ok
> snaraði Jökull hann ór hálsliðunum, fór síðan at leita
> Úlfs ok kom þar at, er þau Syrpa ok hann áttust við, ok
> hafði hon komit Úlfi undir ok grúfði niðr at honum ok
> ætlaði at bíta hann á barkann. 

> Jokull profited from this and made a sudden wrestling move
> where he caught Surtr's heel, so he (Surtr) fell,and
> Jokull twisted off his neck, (he) then went to look for
> Ulfr and came to the place, where they, Syrpa and he, were
> fighting, and she had gotten Ulfr down and crouched down
> by him and intended to bite him in the windpipe.   (Zoega
> koma 4 - koma e-m undir, to get one down, overcome one)

> Jokull put this to use and moved quickly to catch Surt
> with the heel, so he fell and Jokull twisted his neck
> joint out went then to find Ulf and came there to where
> they, Syrpa and he fought and she had overcome Ulf and
> crouched down to him and intended to bite him on the
> throat.

Jökul made use of this and gave Surt a sudden back-heel, so
[that] he fell, and Jökul wrung his neck; then he went to
look for Úlf and came to where Syrpa and he were fighting,
and she had got Úlf down and crouched down by him and
intended to bite him in the windpipe.

The back-heel is a move in which you trip your opponent by
hooking his leg with your heel.

> Jökull tók þá báðum höndum undir kjálkana á kerlingu, en
> setti knén í bakit. 

> With both hands, Jokull took hold of the old woman's
> jawbone and set his knee in her back.     (Zoega taka 12 -
> taka undir e-t, to take hold of a thing)

> Jokull placed then both hands under the old woman’s
> jawbone and set (his) knee on (her) back.

With both hands Jökul took hold under the old woman's
jawbone and set his knee on her back.

> Syrpa mælti: "Skal mik svá grátt leika, Jökull?" 

> Syrpa said: " Will you so maliciously deal with
> me,Jokull?"

> Syrpa spoke, “Shall (you?) thus deal tears? to me,
> Jokull?”

Syrpa said: 'Shall [you] deal so spitefully with me, Jökul?'

The neuter <grátt> is functioning as an adverb.

> "At því mun þér verða," sagði hann ok braut hana síðan á
> bak aftr ór hálsliðunum, ok var hon þegar dauð.

> "You will become that," he said and then broke her back
> from her neck, and she was at once dead.

> “It will happen to you??” said he and broke her back then
> back out of the neck joint, and she was at once dead.

'It will come to that for you,' he said and then forced her
back from the neck joint, and she was dead immediately.

For the first clause I'm taking my cue from <verða> Z8,
<verða at engu> 'come to nothing'.

<Brjóta> Z7: <brjóta á bak> 'to force back'; <aptr> seems
merely to reinforce <á bak>. At any rate the action is
clear enough: he used his grip under her jaw to pull her
head back far enough to break her neck.

> Fór Úlfr þá á fætr ok var stirðr mjök. 
> Ulfr got to his feet and was very stiff.
> Ulf got on his feet then and was very tense?

Úlf then got to his feet and was very stiff.

> Þeir könnuðu síðan hellinn ok fundu þar yfrit mikit góz,
> gull ok silfr ok góð klæði ok marga fáséna gripi. 

> They then searched the cave and found there a large amount
> of property, gold and silver and good clothes and many
> rare costly treasures.

> Then they explored the cave and found all over there many
> goods, gold and silver and good clothing and many rare
> treasures.

Then they explored the cave and found there a great deal of
goods, gold and silver and good clothes and many rare
treasures.

> En er þeir höfðu kannat hellinn, eftir því sem þeira hugr
> var til, gengu þeir í burt ok vildu vitja aftr manna
> sinna, ok er þeir váru komnir skammt á leið, heyrðu þeir
> óp ok háreysti mikit ok allmikla skellihlátra. 

> When they had explored the cave, after that as they became
> aware, they went away and next wanted to visit their men,
> and when they had scarcely come to the trail, they heard a
> shout and much noise and great roaring laughter.

> And when they had explored the cave, after it as (much as)
> they wanted to, they went away and wanted to go back to
> their men and when they had come a short distance on the
> way, they heard shouting and great noise and very great
> roaring laughter.

And when they had explored the cave as much as they were
minded to, they went away and wanted to go back to their
men, and when they had come a short distance on the way they
heard shouting and much noise and great roaring laughter.

> Jökull ok Úlfr sá þá, hvar þeir bræðr váru komnir ok höfðu
> byrðir stórar á herðum sér ok hlupu hverr um annan fram.

> Jokull and Ulfr saw then, where the brothers had come and
> had large boxes on their shoulders each ran in front of
> the other (??).

> Jokull and Ulf saw then where those brothers had come and
> had great boards? on their shoulders and each ran about
> the other forward.

Jökul and Úlf then saw where the brothers had come and had
large loads on their shoulders, and each ran behind another.

In other words, they were running single file. The closest
model that I can find in Zoëga is in <fram> Z4: <bíða fram
um jól> 'to wait until after Yule'. In addition, <umfram>
is 'beyond'. It could still conceivably be 'each ran in
front of another', with ultimately the same basic sense, but
the examples (and others in CV) seem to me to point in the
direction I chose.

<Byrðr> 'burden, load' is cognate with the <burd-> of
English <burden>.

> En er þá bræðr minnst varði, kom Jökull at þeim ok hjó til
> Sáms í höfuðit ok klauf hann í axlir niðr.

> When the brothers became least, Jokull came upon them and
> struck at Sam in the head and split him down in the
> shoulder.

> And when those brothers were least defended, Jokull
> attacked them and hewed at Sam’s head and cleaved him down
> in (the) shoulder.

And when the brothers were least defended, Jökul attacked
them and struck Sám in the head and split him down to the
shoulders.

> Þá hleypr Úlfr at Sniðli með spjótit ok sló undir hnakka
> honum, svá hann lá þar ok sparkaði fótunum. 

> Then Ulfr attacked Snidley with his spear and hit under
> the back of his head, so he lay there and his feet kicked.

> Then Ulf leaps at Snidli with the spear and struck under
> his neck, so he lay there and kicked (his) feet.

Then Úlf attacks Sniðil with his spear and struck under the
back of his head, so [that] he lay there and kicked his
feet.

> Þetta sá Eitill ok kastaði af sér byrðinni. 
> Eitill saw this and threw down this box.
> Eitill saw that and cast his boards? off.

Eitil saw this and threw down his load.

> Hann hafði bitrliga skálm í hendi ok æddi fram til móts
> við þá með miklum jötunmóð ok hjó til Jökuls.

> He had a sharp short sword in his hand and rage forward to
> meet them with much giant-mode and hacked at Jokull.

> He had a sharp short sword in hand and ?? forward to meet
> with them with a great giant’s wrath and hewed at Jokull.

He had a sharp short sword in [his] hand and raged forward
to meet them with great giant's fury and struck at Jökul.

Grace: The verb is <œða>.

> Þat kom á lærit ok varð allmikit sár.
> That came to the thigh and became very much wounded.
> It came on the thigh and became a huge wound.

That hit his thigh and made a huge wound.

'Became' is more literal, but I thought that I'd go for a
good English equivalent instead.

> Kom þá Úlfr, ok sóttu þeir báðir at Eitli, en hann varðist
> alldrengiliga.

> Then Ulfr came, and they both attacked Eitill, but he
> defended himself very valiantly.

> Ulf came then and they both attacked Eitill, but he
> defended himself very manfully.

Then Úlf came, and they both attacked Eitil, but he defended
himself most valiantly.

> Þar kom um síðir, at þeir gátu drepit hann.
> It came there at last, that they were able to slay him.
> At last it happened that they were able to kill him.

At last it happened that they were able to kill him.

> Váru þeir þá bæði móðir ok sárir. 
> They were that both exhausted and wounded.
> They were then both tired and wounded.

They were both exhausted and wounded.

> Þar kom þá Gnípa ok spyrr: "Eruð þit sárir, sveinar?" 

> Then Gnipa came there and asks: " are you two wounded,
> boys"?

> Then Gnipa came there and asks, “Are you two wounded,
> boys?”

Then Gnípa came there and asks: 'Are you two wounded, lads?'

> "Lítit er allt um þat," segir Jökull. 
> "A little is all concerning that," says Jokull
> “It’s nothing??” says Jokull.

'It's no big deal,' says Jökul.

I couldn't resist: it does seem a reasonable translation of
'all concerning that is little'!

Brian